#Resonant Inelastic X-ray Scattering

[mindblowingscience]

MIT physicists and colleagues report new insights into exotic particles key to a form of magnetism that has attracted growing interest because it originates from ultrathin materials only a few atomic layers thick. The work, which could impact future electronics and more, also establishes a new way to study these particles through a powerful instrument at the National Synchrotron Light Source II at Brookhaven National Laboratory. Among their discoveries, the team has identified the microscopic origin of these particles, known as excitons. They showed how they can be controlled by chemically "tuning" the material, which is primarily composed of nickel. Further, they found that the excitons propagate throughout the bulk material instead of being bound to the nickel atoms.

Continue Reading.

[sunaleisocial]

Physicists report new insights into exotic particles key to magnetism

New Post has been published on https://sunalei.org/news/physicists-report-new-insights-into-exotic-particles-key-to-magnetism/

Physicists report new insights into exotic particles key to magnetism

MIT physicists and colleagues report new insights into exotic particles key to a form of magnetism that has attracted growing interest because it originates from ultrathin materials only a few atomic layers thick. The work, which could impact future electronics and more, also establishes a new way to study these particles through a powerful instrument at the National Synchrotron Light Source II at Brookhaven National Laboratory.

Among their discoveries, the team has identified the microscopic origin of these particles, known as excitons. They showed how they can be controlled by chemically “tuning” the material, which is primarily composed of nickel. Further, they found that the excitons propagate throughout the bulk material instead of being bound to the nickel atoms.

Finally, they proved that the mechanism behind these discoveries is ubiquitous to similar nickel-based materials, opening the door for identifying — and controlling — new materials with special electronic and magnetic properties.

The open-access results are reported in the July 12 issue of Physical Review X.

“We’ve essentially developed a new research direction into the study of these magnetic two-dimensional materials that very much relies on an advanced spectroscopic method, resonant inelastic X-ray scattering (RIXS), which is available at Brookhaven National Lab,” says Riccardo Comin, MIT’s Class of 1947 Career Development Associate Professor of Physics and leader of the work. Comin is also affiliated with the Materials Research Laboratory and the Research Laboratory of Electronics.

Comin’s colleagues on the work include Connor A. Occhialini, an MIT graduate student in physics, and Yi Tseng, a recent MIT postdoc now at Deutsches Elektronen-Synchrotron (DESY). The two are co-first authors of the Physical Review X paper.

Additional authors are Hebatalla Elnaggar of the Sorbonne; Qian Song, a graduate student in MIT’s Department of Physics; Mark Blei and Seth Ariel Tongay of Arizona State University; Frank M. F. de Groot of Utrecht University; and Valentina Bisogni and Jonathan Pelliciari of Brookhaven National Laboratory.

Ultrathin layers

The magnetic materials at the heart of the current work are known as nickel dihalides. They are composed of layers of nickel atoms sandwiched between layers of halogen atoms (halogens are one family of elements), which can be isolated to atomically thin layers. In this case, the physicists studied the electronic properties of three different materials composed of nickel and the halogens chlorine, bromine, or iodine. Despite their deceptively simple structure, these materials host a rich variety of magnetic phenomena.

The team was interested in how these materials’ magnetic properties respond when exposed to light. They were specifically interested in particular particles — the excitons — and how they are related to the underlying magnetism. How exactly do they form? Can they be controlled?

Enter excitons

A solid material is composed of different types of elementary particles, such as protons and electrons. Also ubiquitous in such materials are “quasiparticles” that the public is less familiar with. These include excitons, which are composed of an electron and a “hole,” or the space left behind when light is shone on a material and energy from a photon causes an electron to jump out of its usual position.

Through the mysteries of quantum mechanics, however, the electron and hole are still connected and can “communicate” with each other through electrostatic interactions. This interaction leads to a new composite particle formed by the electron and the hole — an exciton.

Excitons, unlike electrons, have no charge but possess spin. The spin can be thought of as an elementary magnet, in which the electrons are like little needles orienting in a certain way. In a common refrigerator magnet, the spins all point in the same direction. Generally speaking, the spins can organize in other patterns leading to different kinds of magnets. The unique magnetism associated with the nickel dihalides is one of these less-conventional forms, making it appealing for fundamental and applied research.

The MIT team explored how excitons form in the nickel dihalides. More specifically, they identified the exact energies, or wavelengths, of light necessary for creating them in the three materials they studied.

“We were able to measure and identify the energy necessary to form the excitons in three different nickel halides by chemically ‘tuning,’ or changing, the halide atom from chlorine to bromine to iodine,” says Occhialini. “This is one essential step towards understanding how photons — light — could one day be used to interact with or monitor the magnetic state of these materials.” Ultimate applications include quantum computing and novel sensors.

The work could also help predict new materials involving excitons that might have other interesting properties. Further, while the studied excitons originate on the nickel atoms, the team found that they do not remain localized to these atomic sites. Instead, “we showed that they can effectively hop between sites throughout the crystal,” Occhialini says. “This observation of hopping is the first for these types of excitons, and provides a window into understanding their interplay with the material’s magnetic properties.”

A special instrument

Key to this work — in particular for observing the exciton hopping — is resonant inelastic X-ray scattering (RIXS), an experimental technique that co-authors Pelliciari and Bisogni helped pioneer. Only a few facilities in the world have advanced high energy resolution RIXS instruments. One is at Brookhaven. Pelliciari and Bisogni are part of the team running the RIXS facility at Brookhaven. Occhialini will be joining the team there as a postdoc after receiving his MIT PhD.

RIXS, with its specific sensitivity to the excitons from the nickel atoms, allowed the team to “set the basis for a general framework for nickel dihalide systems,” says Pelliciari. “it allowed us to directly measure the propagation of excitons.”

This work was supported by the U.S. Department of Energy Basic Energy Science and Brookhaven National Laboratory through the Co-design Center for Quantum Advantage (C2QA), a DoE Quantum Information Science Research Center.

[jcmarchi]

Physicists report new insights into exotic particles key to magnetism

New Post has been published on https://thedigitalinsider.com/physicists-report-new-insights-into-exotic-particles-key-to-magnetism/

Physicists report new insights into exotic particles key to magnetism

MIT physicists and colleagues report new insights into exotic particles key to a form of magnetism that has attracted growing interest because it originates from ultrathin materials only a few atomic layers thick. The work, which could impact future electronics and more, also establishes a new way to study these particles through a powerful instrument at the National Synchrotron Light Source II at Brookhaven National Laboratory.

Among their discoveries, the team has identified the microscopic origin of these particles, known as excitons. They showed how they can be controlled by chemically “tuning” the material, which is primarily composed of nickel. Further, they found that the excitons propagate throughout the bulk material instead of being bound to the nickel atoms.

Finally, they proved that the mechanism behind these discoveries is ubiquitous to similar nickel-based materials, opening the door for identifying — and controlling — new materials with special electronic and magnetic properties.

The open-access results are reported in the July 12 issue of Physical Review X.

“We’ve essentially developed a new research direction into the study of these magnetic two-dimensional materials that very much relies on an advanced spectroscopic method, resonant inelastic X-ray scattering (RIXS), which is available at Brookhaven National Lab,” says Riccardo Comin, MIT’s Class of 1947 Career Development Associate Professor of Physics and leader of the work. Comin is also affiliated with the Materials Research Laboratory and the Research Laboratory of Electronics.

Comin’s colleagues on the work include Connor A. Occhialini, an MIT graduate student in physics, and Yi Tseng, a recent MIT postdoc now at Deutsches Elektronen-Synchrotron (DESY). The two are co-first authors of the Physical Review X paper.

Additional authors are Hebatalla Elnaggar of the Sorbonne; Qian Song, a graduate student in MIT’s Department of Physics; Mark Blei and Seth Ariel Tongay of Arizona State University; Frank M. F. de Groot of Utrecht University; and Valentina Bisogni and Jonathan Pelliciari of Brookhaven National Laboratory.

Ultrathin layers

The magnetic materials at the heart of the current work are known as nickel dihalides. They are composed of layers of nickel atoms sandwiched between layers of halogen atoms (halogens are one family of elements), which can be isolated to atomically thin layers. In this case, the physicists studied the electronic properties of three different materials composed of nickel and the halogens chlorine, bromine, or iodine. Despite their deceptively simple structure, these materials host a rich variety of magnetic phenomena.

The team was interested in how these materials’ magnetic properties respond when exposed to light. They were specifically interested in particular particles — the excitons — and how they are related to the underlying magnetism. How exactly do they form? Can they be controlled?

Enter excitons

A solid material is composed of different types of elementary particles, such as protons and electrons. Also ubiquitous in such materials are “quasiparticles” that the public is less familiar with. These include excitons, which are composed of an electron and a “hole,” or the space left behind when light is shone on a material and energy from a photon causes an electron to jump out of its usual position.

Through the mysteries of quantum mechanics, however, the electron and hole are still connected and can “communicate” with each other through electrostatic interactions. This interaction leads to a new composite particle formed by the electron and the hole — an exciton.

Excitons, unlike electrons, have no charge but possess spin. The spin can be thought of as an elementary magnet, in which the electrons are like little needles orienting in a certain way. In a common refrigerator magnet, the spins all point in the same direction. Generally speaking, the spins can organize in other patterns leading to different kinds of magnets. The unique magnetism associated with the nickel dihalides is one of these less-conventional forms, making it appealing for fundamental and applied research.

The MIT team explored how excitons form in the nickel dihalides. More specifically, they identified the exact energies, or wavelengths, of light necessary for creating them in the three materials they studied.

“We were able to measure and identify the energy necessary to form the excitons in three different nickel halides by chemically ‘tuning,’ or changing, the halide atom from chlorine to bromine to iodine,” says Occhialini. “This is one essential step towards understanding how photons — light — could one day be used to interact with or monitor the magnetic state of these materials.” Ultimate applications include quantum computing and novel sensors.

The work could also help predict new materials involving excitons that might have other interesting properties. Further, while the studied excitons originate on the nickel atoms, the team found that they do not remain localized to these atomic sites. Instead, “we showed that they can effectively hop between sites throughout the crystal,” Occhialini says. “This observation of hopping is the first for these types of excitons, and provides a window into understanding their interplay with the material’s magnetic properties.”

A special instrument

Key to this work — in particular for observing the exciton hopping — is resonant inelastic X-ray scattering (RIXS), an experimental technique that co-authors Pelliciari and Bisogni helped pioneer. Only a few facilities in the world have advanced high energy resolution RIXS instruments. One is at Brookhaven. Pelliciari and Bisogni are part of the team running the RIXS facility at Brookhaven. Occhialini will be joining the team there as a postdoc after receiving his MIT PhD.

RIXS, with its specific sensitivity to the excitons from the nickel atoms, allowed the team to “set the basis for a general framework for nickel dihalide systems,” says Pelliciari. “it allowed us to directly measure the propagation of excitons.”

This work was supported by the U.S. Department of Energy Basic Energy Science and Brookhaven National Laboratory through the Co-design Center for Quantum Advantage (C2QA), a DoE Quantum Information Science Research Center.

[thelegend9798]

Spin keeps electrons in line in iron-based superconductor

Spin keeps electrons in line in iron-based superconductor

Resonant inelastic X-ray scattering reveals high-energy nematic spin correlations in the nematic state of the iron-based superconductor, FeSe. Image: Beijing Normal University/Qi Tang and Xingye Lu. Credit: Beijing Normal University/Qi Tang and Xingye Lu Researchers from PSI’s Spectroscopy of Quantum Materials group together with scientists from Beijing Normal University have solved a puzzle at…

[frankkjonestx]

New discovery to have huge impact on development of future battery cathodes

A new article reveals how researchers fully identified the nature of oxidized oxygen in the important battery material - Li-rich NMC - using RIXS (Resonant Inelastic X-ray Scattering). This compound is being closely considered for implementation in next generation Li-ion batteries because it delivers higher energy density than current materials, and could translate to longer driving ranges for electric vehicles and enable scientists to tackle issues like battery longevity and voltage fade. from Tips By Frank https://www.sciencedaily.com/releases/2020/09/200921111711.htm

[ruggerorespigo]

New discovery to have huge impact on development of future battery cathodes

A new article reveals how researchers fully identified the nature of oxidized oxygen in the important battery material - Li-rich NMC - using RIXS (Resonant Inelastic X-ray Scattering). This compound is being closely considered for implementation in next generation Li-ion batteries because it delivers higher energy density than current materials, and could translate to longer driving ranges for electric vehicles and enable scientists to tackle issues like battery longevity and voltage fade. Latest Science News -- ScienceDaily https://www.sciencedaily.com/releases/2020/09/200921111711.htm

[inerginc]

via Batteries News -- ScienceDaily A new article reveals how researchers fully identified the nature of oxidized oxygen in the important battery material - Li-rich NMC - using RIXS (Resonant Inelastic X-ray Scattering). This compound is being closely considered for implementation in next generation Li-ion batteries because it delivers higher energy density than current materials, and could translate to longer driving ranges for electric vehicles and enable scientists to tackle issues like battery longevity and voltage fade.

[sciencespies]

Unraveling the stripe order mystery

https://sciencespies.com/physics/unraveling-the-stripe-order-mystery/

Unraveling the stripe order mystery

Doped charges in the CuO2 planes of cuprate superconductors form regular one-dimensional ‘stripes’ at low temperatures. Excitation with ultrafast near-infrared pulses allows direct observation of diffusive charge dynamics, which may be involved in the establishing in-plane superconductivity. Credit: Greg Stewart/SLAC National Accelerator Laboratory

One of the greatest mysteries in condensed matter physics is the exact relationship between charge order and superconductivity in cuprate superconductors. In superconductors, electrons move freely through the material—there is zero resistance when it’s cooled below its critical temperature. However, the cuprates simultaneously exhibit superconductivity and charge order in patterns of alternating stripes. This is paradoxical in that charge order describes areas of confined electrons. How can superconductivity and charge order coexist?

Now researchers at the University of Illinois at Urbana-Champaign, collaborating with scientists at the SLAC National Accelerator Laboratory, have shed new light on how these disparate states can exist adjacent to one another. Illinois Physics post-doctoral researcher Matteo Mitrano, Professor Peter Abbamonte, and their team applied a new X-ray scattering technique, time-resolved resonant soft X-ray scattering, taking advantage of the state-of-the-art equipment at SLAC. This method enabled the scientists to probe the striped charge order phase with an unprecedented energy resolution. This is the first time this has been done at an energy scale relevant to superconductivity.

The scientists measured the fluctuations of charge order in a prototypical copper-oxide superconductor, La2-xBaxCuO4 (LBCO) and found the fluctuations had an energy that matched the material’s superconducting critical temperature, implying that superconductivity in this material—and by extrapolation, in the cuprates—may be mediated by charge-order fluctuations.

The researchers further demonstrated that, if the charge order melts, the electrons in the system will reform the striped areas of charge order within tens of picoseconds. As it turns out, this process obeys a universal scaling law. To understand what they were seeing in their experiment, Mitrano and Abbamonte turned to Illinois Physics Professor Nigel Goldenfeld and his graduate student Minhui Zhu, who were able to apply theoretical methods borrowed from soft condensed matter physics to describe the formation of the striped patterns.

These findings were published on August 16, 2019, in the online journal Science Advances.

Cuprates have stripes

The significance of this mystery can be understood within the context of research in high-temperature superconductors (HTS), specifically the cuprates—layered materials that contain copper complexes. The cuprates, some of the first discovered HTS, have significantly higher critical temperatures than “ordinary” superconductors (e.g., aluminum and lead superconductors have a critical temperature below 10 K). In the 1980s, LBCO, a cuprate, was found to have a superconducting critical temperature of 35 K (-396°F), a discovery for which Bednorz and Müller won the Nobel Prize.

That discovery precipitated a flood of research into the cuprates. In time, scientists found experimental evidence of inhomogeneities in LBCO and similar materials: insulating and metallic phases that were coexisting. In 1998, Illinois Physics Professor Eduardo Fradkin, Stanford Professor Steven Kivelson, and others proposed that Mott insulators—materials that ought to conduct under conventional band theory but insulate due to repulsion between electrons—are able to host stripes of charge order and superconductivity. La2CuO4, the parent compound of LBCO, is an example of a Mott insulator. As Ba is added to that compound, replacing some La atoms, stripes form due to the spontaneous organization of holes—vacancies of electrons that act like positive charges.

Still, other questions regarding the behavior of the stripes remained. Are the areas of charge order immobile? Do they fluctuate?

“The conventional belief is that if you add these doped holes, they add a static phase which is bad for superconductivity—you freeze the holes, and the material cannot carry electricity,” Mitrano comments. “If they are dynamic—if they fluctuate—then there are ways in which the holes could aid high-temperature superconductivity.”

Probing the fluctuations in LBCO

To understand what exactly the stripes are doing, Mitrano and Abbamonte conceived of an experiment to melt the charge order and observe the process of its reformation in LBCO. Mitrano and Abbamonte reimagined a measurement technique called resonant inelastic X-ray scattering, adding a time-dependent protocol to observe how the charge order recovers over a duration of 40 picoseconds. The team shot a laser at the LBCO sample, imparting extra energy into the electrons to melt the charge order and introduce electronic homogeneity.

“We used a novel type of spectrometer developed for ultra-fast sources, because we are doing experiments in which our laser pulses are extremely short,” Mitrano explains. “We performed our measurements at the Linac Coherent Light Source at SLAC, a flagship in this field of investigation. Our measurements are two orders of magnitude more sensitive in energy than what can be done at any other conventional scattering facility.”

Professor Peter Abbamonte (middle, in navy sweater) and postdoctoral researcher Matteo Mitrano (right, in white dress shirt) pose with their team at the SLAC National Accelerator Laboratory in Menlo Park, California. The experimental team used a new investigative technique called time-resolved resonant soft x-ray scattering, to probe the striped charge order phase in a well-studied cuprate superconductor, with an unprecedented energy resolution, finding that superconductivity in cuprates may be mediated by charge-order fluctuations. This is the first time such an experiment has been done at an energy scale relevant to superconductivity. Credit: SLAC

Abbamonte adds, “What is innovative here is using time-domain scattering to study collective excitations at the sub-meV energy scale. This technique was demonstrated previously for phonons. Here, we have shown the same approach can be applied to excitations in the valence band.”

Hints of a mechanism for superconductivity

The first significant result of this experiment is that the charge order does in fact fluctuate, moving with an energy that almost matches the energy established by the critical temperature of LBCO. This suggests that Josephson coupling may be crucial for superconductivity.

The idea behind the Josephson effect, discovered by Brian Josephson in 1962, is that two superconductors can be connected via a weak link, typically an insulator or a normal metal. In this type of system, superconducting electrons can leak from the two superconductors into the weak link, generating within it a current of superconducting electrons.

Josephson coupling provides a possible explanation for the coupling between superconductivity and striped regions of charge order, wherein the stripes fluctuate such that superconductivity leaks into the areas of charge order, the weak links.

Obeying universal scaling laws of pattern formation

After melting the charge order, Mitrano and Abbamonte measured the recovery of the stripes as they evolved in time. As the charge order approached its full recovery, it followed an unexpected time dependence. This result was nothing like what the researchers had encountered in the past. What could possibly explain this?

The answer is borrowed from the field of soft condensed matter physics, and more specifically from a scaling law theory Goldenfeld had developed two decades prior to describe pattern formation in liquids and polymers. Goldenfeld and Zhu demonstrated the stripes in LBCO recover according to a universal, dynamic, self-similar scaling law.

Goldenfeld explains, “By the mid-1990s, scientists had an understanding of how uniform systems approach equilibrium, but how about stripe systems? I worked on this question about 20 years ago, looking at the patterns that emerge when a fluid is heated from below, such as the hexagonal spots of circulating, upwelling white flecks in hot miso soup. Under some circumstances these systems form stripes of circulating fluid, not spots, analogous to the stripe patterns of electrons in the cuprate superconductors. And when the pattern is forming, it follows a universal scaling law. This is exactly what we see in LBCO as it reforms its stripes of charge order.”

Through their calculations, Goldenfeld and Zhu were able to elucidate the process of time-dependent pattern reformation in Mitrano and Abbamonte’s experiment. The stripes reform with a logarithmic time dependence—a very slow process. Adherence to the scaling law in LBCO further implies that it contains topological defects, or irregularities in its lattice structure. This is the second significant result from this experiment.

Zhu comments, “It was exciting to be a part of this collaborative research, working with solid-state physicists, but applying techniques from soft condensed matter to analyze a problem in a strongly correlated system, like high-temperature superconductivity. I not only contributed my calculations, but also picked up new knowledge from my colleagues with different backgrounds, and in this way gained new perspectives on physical problems, as well as new ways of scientific thinking.”

In future research, Mitrano, Abbamonte, and Goldenfeld plan to further probe the physics of charge order fluctuations with the goal of completely melting the charge order in LBCO to observe the physics of stripe formation. They also plan similar experiments with other cuprates, including yttrium barium copper oxide compounds, better known as YBCO.

Goldenfeld sees this and future experiments as ones that could catalyze new research in HTS: “What we learned in the 20 years since Eduardo Fradkin and Steven Kivelson’s work on the periodic modulation of charge is that we should think about the HTS as electronic liquid crystals,” he states. “We’re now starting to apply the soft condensed matter physics of liquid crystals to HTS to understand why the superconducting phase exists in these materials.”

Explore further

For superconductors, discovery comes from disorder

More information: “Ultrafast time-resolved x-ray scattering reveals diffusive charge order dynamics in La2–xBaxCuO4” Science Advances (2019). DOI: 10.1126/sciadv.aax3346 , https://advances.sciencemag.org/content/5/8/eaax3346

Provided by University of Illinois at Urbana-Champaign

Citation: Unraveling the stripe order mystery (2019, August 16) retrieved 16 August 2019 from https://phys.org/news/2019-08-unraveling-stripe-mystery.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

#Physics

[fumpkins]

Classic double-slit experiment in a new light

An intense beam of high-energy X-ray photons (violet) hits two adjacent iridium atoms (green) in the crystal. This excites electrons in the atoms for a short time. The atoms emit X-ray photons which overlap behind the two iridium atoms (red) and can be analyzed as interference images. Credit: Markus Grueninger, University of Cologne

An international research team led by physicists from the University of Cologne has implemented a new variant of the basic double-slit experiment using resonant inelastic X-ray scattering at the European Synchrotron ESRF in Grenoble. This new variant offers a deeper understanding of the electronic structure of solids. Writing in Science Advances, the research group have now presented their results in a study titled “Resonant inelastic X-ray incarnation of Young’s double-slit experiment.”

The double-slit experiment is of fundamental importance in physics. More than 200 years ago, Thomas Young diffracted light at two adjacent slits, thus generating interference patterns (images based on superposition) behind this double slit. Thus, he demonstrated the wave nature of light. In the 20th century, scientists have shown that electrons or molecules scattered on a double slit show the same interference pattern, which contradicts the classical expectation of particle behaviour, but can be explained in quantum-mechanical wave-particle dualism. In contrast, the researchers in Cologne investigated an iridium oxide crystal (Ba3CeIr2O9) by means of resonant inelastic X-ray scattering (RIXS).

The crystal is irradiated with strongly collimated, high-energy X-ray photons. The X-rays are scattered by the iridium atoms in the crystal, which take over the role of the slits in Young’s classical experiment. Due to the rapid technical development of RIXS and a skilful choice of crystal structure, the physicists were observed the scattering on two adjacent iridium atoms, a so-called dimer.

An international research team has implemented a new variant of the basic double-slit experiment using resonant inelastic X-ray scattering at the European Synchrotron ESRF in Grenoble. Credit: ESRF/Jayet

“The interference pattern tells us a lot about the scattering object, the dimer double slit,” says Professor Markus Grueninger, who heads the research group at the University of Cologne. In contrast to the classical double-slit experiment, the inelastically scattered X-ray photons provide information about the excited states of the dimer, in particular their symmetry, and thus about the dynamic physical properties of the solid.

These RIXS experiments require a modern synchrotron as an extremely brilliant X-ray light source and a sophisticated experimental setup. To specifically excite only the iridium atoms, scientists have to select the very small proportion of photons with the right energy from the broad spectrum of the synchrotron, and the scattered photons are selected even more strictly according to energy and direction of scattering. Only a few photons remain. With the required accuracy, these RIXS experiments are currently only possible at two synchrotrons worldwide, including the ESRF (European Synchrotron Radiation Facility) in Grenoble, where the team from Cologne conducted their experiment.

The two adjacent iridium atoms (dimer) are shown in green. The elements oxygen (O, red), barium (Ba, grey) and cerium (Ce, turquoise) are also involved in the crystal structure. Credit: Markus Grueninger, University of Cologne

“With our RIXS experiment, we were able to prove a fundamental theoretical prediction from 1994. This opens a new door for a whole series of further experiments that will allow us to gain a deeper understanding of the properties and functionalities of solids,” says Grueninger.

Explore further: Which-way detector unlocks some mystery of the double-slit experiment

More information: Resonant inelastic x-ray incarnation of Young’s double-slit experiment. Science Advances (2019). advances.sciencemag.org/content/5/1/eaav4020

Journal reference: Science Advances

Provided by: University of Cologne

New post published on: https://www.livescience.tech/2019/01/18/classic-double-slit-experiment-in-a-new-light/

[qutronics]

via QuNews

[inhandnetworks-blog]

Researchers Rev mri remote monitoring  eal Hidden Magnetic Waves in High-Temperature Superconductors

www.inhandnetworks.com

In this rendering, never-before-seen magnetic excitations ripple through a high-temperature superconductor, revealed for the first time by the Resonant Inelastic X-ray Scattering technique. By measuring the precise energy change of beams of incident x-rays (blue arrow) as they struck these quantum ripples and bounced off (red arrow), scientists discovered excitations present throughout the entire LSCO phase diagram.

New research from the Brookhaven National Laboratory has revealed that magnetic excitations, quantum waves believed by many to regulate high-temperature superconductors, exist in both non-superconducting and superconducting materials.

Upton, New York —Intrinsic inefficiencies plague current systems for the generation and delivery of electricity, with significant energy lost in transit. High-temperature superconductors (HTS)—uniquely capable of transmitting electricity with zero loss when chilled to subzero temperatures—could revolutionize the planet’s aging and imperfect energy infrastructure, but the remarkable materials remain fundamentally puzzling to physicists. To  IoT Remote Monitoring  unlock the true potential of HTS technology, scientists must navigate a quantum-scale labyrinth and pin down the phenomenon’s source.

Now, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and other collaborating institutions have discovered a surprising twist in the magnetic properties of HTS, challenging some of the leading theories. In a new study, published online in the journal Nature Materials on August 4, 2013, scientists found that unexpected magnetic excitations—quantum waves believed by many to regulate HTS—exist in both non-superconducting and superconducting materials.

“This is a major experimental clue about which magnetic excitations are important for high-temperature superconductivity,” said Mark Dean, a physicist at Brookhaven Lab and lead author on the new paper. “Cutting-edge x-ray scattering techniques allowed us to see excitations in samples previously thought to be essentially non-magnetic.”

On the atomic scale, electron spins—a bit like tiny bar magnets pointed in specific directions—rapidly interact with each other throughout magnetic materials. When one spin rotates, this disturbance can propagate through the material as a wave, tipping and aligning the spins of neighboring electrons. Many researchers believe that this subtle excitation wave may bind electrons together to create the perfect c att certified  urrent conveyance of HTS, which operates at slightly warmer temperatures than traditional superconductivity.

“Proving or disproving this hypothesis remains one of the holy grails of condensed matter physics research,” Dean said. “This discovery gives us a new way to evaluate rival theories of HTS.”

Perfectly Dope

Superconductivity demands extremely cold conditions and a precise chemical recipe. Beyond selecting the right elements from the periodic table, physicists carefully tweak the electron content of atoms through a process called doping. Doping determines the average number of electrons present in each atom, and in turn dictates both the behavior of spin waves and the presence of HTS, which emerges around a particular doping sweet spot.

For this study, the team examined thin films of lanthanum, strontium, copper, and oxygen—often abbreviated as LSCO. These particular HTS materials can be tuned to exhibit a wide range of different electronic behaviors.

“This is the only system that lets us examine the entire phase diagram, from a strongly correlated insulator all the way to a non-superconducting metal,” said Brookhaven physicist John Hill, coauthor on the paper. “We could measure magnetic excitations both before and after the ideal doping levels for superconductivity.”

To grow these materials, Brookhaven Lab physicist Ivan Bozovic—another author on the study—used a custom-built atomic layer-by-layer molecular beam epitaxy machine (ALL-MBE). Bozovic’s system is uniquely equipped to monitor the synthesis of the LSCO films in real-time, giving him an unparalleled degree of control over the atomic composition of each layer, including adjustments to the doping levels.

“Ivan grows these beautiful, fantastic films,” Hill said. “His samples are highly uniform with flat, mirror-like surfaces. This helps enormously when trying to pin down the subtleties of how these samples scatter x-rays.”

Measuring a Quantum Sea

The quantum ripples themselves have wavelengths measured on the Ångstrom scale—smaller than one billionth of a meter. To detect these tiny fluctuations, the scientists applied a technique called resonant inelastic x-ray scattering (RIXS) to the full range of LSCO films. The measurements were taken with the Advanced X-ray Emission Spectrometer at the European Synchrotron Radiation Facility (ESRF) in France. The design, construction, and commissioning of this instrument was led by Giacomo Ghiringhelli and Lucio Braicovich at the Politecnico di Milano in Italy and by Nick Brookes at the ESRF. The Brookhaven Lab team worked in close collaboration with these scientists to perform the RIXS measurements.

“This instrument allowed us to precisely measure how much energy the x-rays lost when they struck each LSCO sample,” Dean said. “We could then pinpoint the presence or absence of magnetic excitations and track them across all the different doping levels.”

Earlier studies using neutron scattering found that magnetic excitations appeared to vanish in the overdoped LSCO samples, bolstering the prominent theory that the waves play an essential role in superconductivity. The RIXS technique, however, is much more sensitive to magnetic excitations with certain wavelengths and capable of detecting otherwise imperceptible signals.

“Discovering excitations that do not depend on doping levels means that the relationship between HTS and the waves in these films is more intricate than we suspected,” Hill said.

Brighter Beams and Better Superconductors

RIXS is currently able to detect magnetic excitations with a precision, or energy resolution, of about 100 milli-electron volts. Bu vending inventory management t as scientists seek more fundamental phenomena, even greater accuracy and sensitivity is required. Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II), expected to start operating in 2015, will produce some of the brightest x-rays in the world. The Soft Inelastic X-ray beamline under construction at NSLS-II promises unprecedented energy resolution for HTS investigations.

“Ultimately, the RIXS energy resolution is still not as good as we’d like,” Dean said. “NSLS-II is going to be huge for the superconductivity game—absolutely huge. We’ll be able to see excitations down at 10 milli-electron volts, and there should be real breakthroughs hidden there.”

Solving the mystery of high-temperature superconductivity could radically improve technology ranging from wind turbines to medical imaging devices. But to manipulate the perfect electricity conveyance possible in HTS materials and possibly bring them up to room temperature, theorists must transform these experimental results into universally applicable rules.

“The joke is that HTS has in fact already been solved, but we just don’t know which of the many competing theories is the right one,” Hill said. “Our discovery was actually predicted by a few groups, and we’re excited to see them leap on the results and drive our understanding forward. The work is fundamentally interesting, yes, but the potential applications are really exciting.”

The research was funded through Brookhaven Lab’s Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the U.S. Department of Energy’s Office of Science to seek understanding of the underlying nature of superconductivity in complex materials.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

Publication: M. P. M. Dean, et al., “Persistence of magnetic excitations in La2−xSrxCuO4 from the undoped insulator to the heavily overdoped non-superconducting metal,” Nature Materials, 2013; doi:10.1038/nmat3723

Image: Brookhaven National Laboratory

Industrial VPN router, Dual SIM M2M router, Industrial LTE Router, Industrial LTE router, industrial 4G/3G router, router industrial, cost-effective industrial LTE router, Industrial LTE Router, Industrial LTE router, industrial IoT router, router industrial, cost-effective M2M router, M2M LTE router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Industrial 3G Router , Industrial 3g router, industrial wireless router, VPN router, DIN-Rail router, cellular router, Distribution Power Line Monitoring System, Overhead Line Monitoring, Distribution Power Line Monitoring, Fault detection & location, Grid Analytics System, Remote Machine Monitoring & Maintenance System, IoT Remote Monitoring, Prognostics and Health Management, Remote connectivity, Remote Maintenance, Smart Vending, smart vending, InHandGo, retrofit, touchscreen vending, cashless vending, cloud VMS, Transformer Monitoring, Transformer Monitoring, substation monitoring, grid LTE router, wireless communication, smart grid, Remote Automation, Remote Automation, Secure remote networks, web SCADA, Remote Diagnostics, Remote PLC programming, Intelligent Traffic Enforcement, Intelligent Traffic Enforcement, wireless networking, cellular router, Wireless ATM Solution, Wireless ATM, ATM Remote Diagnostic, prestashop 多语商城, opencart 外��商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设, 华人网站维护, 华人网络兼职, china webdesign, webdesign, seo, joomla web design, 香港網頁設計, 網站建設, 企業建站, 商城網站, 集團網站, 海外網站, 營銷網站, 網站推廣, web design, joomla webdesign, wordpress webdesign, opencart webdesign, magento webdesign, durpal webdesign, vtiger crm, adempiere erp, compiere erp, hosting, domains, vps, email marketing, joomla 网页设计, wordpress 建站, magento 大型外贸商城, durpal 门户网站, seo 网站推广, 网站自然排名, joomla 網站製作, wordpress 定制開發, opencart 維護修改, prestashop 模板修改, magento 培訓實施, durpal 定制修改, seo 營銷推廣, 外鏈收錄排位, joomla, wordpress, opencart, prestashop, magento, durpal, zencart, crm, erp, edm, marketing, joomla template, wordpress themes, magento themes, opencart themes, prestashop themes, 崀山, 崀山科技, 崀山科技全球服务中心, LangShan Technology Global Service Center, LangShan Technology, langshantech, LangShan, china webdesign, 網頁製作, 網頁設計, 企业建站, 企業建站, 在線商城, 營銷網站, 網站推廣, 網站營銷, 排名推廣, 產品推廣, 主機維護, 公司兼職, 網站SEO, joomla seo, wordpress seo, joomla 網站推廣, opencart 網站推廣, prestashop 網站推廣, wordpress 網站推廣, magento 網站推廣, joomla 網站排名, prestashop 網站排名, wordpress 網站排名, opencart 網站排名, prestashop 多语商城, opencart 外贸商城, 网页设计, 网站建设, 企业建站, 商城网站, 集团网站, 海外网站, 营销网站, 网站推广, 华人网站建设,

[viralpearl-blog]

Classic double-slit experiment in a new light -- ScienceDaily

Classic double-slit experiment in a new light — ScienceDaily

An international research team led by physicists from Collaborative Research Centre 1238, ��Control and Dynamics of Quantum Materials’ at the University of Cologne has implemented a new variant of the basic double-slit experiment using resonant inelastic X-ray scattering at the European Synchrotron ESRF in Grenoble. This new variant offers a deeper understanding of the electronic structure of…

[arxiv-physics]

[ Authors ] Marie Preuße, Sergey I. Bokarev, Saadullah G. Aziz, Oliver Kühn [ Abstract ] The Frenkel exciton model was adapted to describe X-ray absorption and resonant inelastic scattering spectra of polynuclear transition metal complexes by means of restricted active space self-consistent field method. The proposed approach allows to substantially decrease the requirements to computational resources if compared to a full supermolecular quantum chemical treatment. This holds true in particular in cases where the dipole approximation to the electronic transition charge density can be applied. The computational protocol was applied to the calculation of X-ray spectra of the hemin complex, which forms dimers in aqueous solution. The aggregation effects were found to be comparable to the spectral alterations due to the replacement of the axial ligand by solvent molecules.

[aidloindia-blog]

CBSE Class 11th Physics Syllabus

Unit I: Physical World and Measurement 10 Periods

Chapter–1: Physical World Physics-scope and excitement; nature of physical laws; Physics, technology and society. Chapter–2: Units and Measurements Need for measurement: Units of measurement; systems of units; SI units, fundamental and derived units. Length, mass and time measurements; accuracy and precision of measuring instruments; errors in measurement; significant figures. Dimensions of physical quantities, dimensional analysis and its applications.

Unit II: Kinematics 20 Periods

Chapter–3: Motion in a Straight Line Frame of reference, Motion in a straight line: Position-time graph, speed and velocity. Elementary concepts of differentiation and integration for describing motion, uniform and non-uniform motion, average speed and instantaneous velocity, uniformly accelerated motion, velocity - time and position-time graphs. Relations for uniformly accelerated motion (graphical treatment). Chapter–4: Motion in a Plane Scalar and vector quantities; position and displacement vectors, general vectors and their notations; equality of vectors, multiplication of vectors by a real number; addition and subtraction of vectors, relative velocity, Unit vector; resolution of a vector in a plane, rectangular components, Scalar and Vector product of vectors. Motion in a plane, cases of uniform velocity and uniform acceleration-projectile motion, uniform circular motion.

Unit III: Laws of Motion 14 Periods

Chapter–5: Laws of Motion Intuitive concept of force, Inertia, Newton's first law of motion; momentum and Newton's second law of motion; impulse; Newton's third law of motion. Law of conservation of linear momentum and its applications. Equilibrium of concurrent forces, Static and kinetic friction, laws of friction, rolling friction, lubrication. Dynamics of uniform circular motion: Centripetal force, examples of circular motion (vehicle on a level circular road, vehicle on a banked road).

Unit IV: Work, Energy and Power 12 Periods

Chapter–6: Work, Engery and Power Work done by a constant force and a variable force; kinetic energy, work-energy theorem, power. Notion of potential energy, potential energy of a spring, conservative forces: conservation of mechanical energy (kinetic and potential energies); non-conservative forces: motion in a vertical circle; elastic and inelastic collisions in one and two dimensions.

Unit V: Motion of System of Particles and Rigid Body 18 Periods

Chapter–7: System of Particles and Rotational Motion Centre of mass of a two-particle system, momentum conservation and centre of mass motion. Centre of mass of a rigid body; centre of mass of a uniform rod. Moment of a force, torque, angular momentum, law of conservation of angular momentum and its applications. Equilibrium of rigid bodies, rigid body rotation and equations of rotational motion, comparison of linear and rotational motions. Moment of inertia, radius of gyration, values of moments of inertia for simple geometrical objects (no derivation). Statement of parallel and perpendicular axes theorems and their applications.

Unit VI: Gravitation 12 Periods

Chapter–8: Gravitation Kepler's laws of planetary motion, universal law of gravitation. Acceleration due to gravity and its variation with altitude and depth. Gravitational potential energy and gravitational potential, escape velocity, orbital velocity of a satellite, Geo-stationary satellites.

Unit VII: Properties of Bulk Matter 20 Periods

Chapter–9: Mechanical Properties of Solids Elastic behaviour, Stress-strain relationship, Hooke's law, Young's modulus, bulk modulus, shear modulus of rigidity, Poisson's ratio; elastic energy. Chapter–10: Mechanical Properties of Fluids Pressure due to a fluid column; Pascal's law and its applications (hydraulic lift and hydraulic brakes), effect of gravity on fluid pressure. Viscosity, Stokes' law, terminal velocity, streamline and turbulent flow, critical velocity, Bernoulli's theorem and its applications. Surface energy and surface tension, angle of contact, excess of pressure across a curved surface, application of surface tension ideas to drops, bubbles and capillary rise. Chapter–11: Thermal Properties of Matter Heat, temperature, thermal expansion; thermal expansion of solids, liquids and gases, anomalous expansion of water; specific heat capacity; Cp, Cv - calorimetry; change of state - latent heat capacity. Heat transfer-conduction, convection and radiation, thermal conductivity, qualitative ideas of Blackbody radiation, Wein's displacement Law, Stefan's law, Green house effect.

Unit VIII: Thermodynamics 12 Periods

Chapter–12: Thermodynamics Thermal equilibrium and definition of temperature (zeroth law of thermodynamics), heat, work and internal energy. First law of thermodynamics, isothermal and adiabatic processes. Second law of thermodynamics: reversible and irreversible processes, Heat engine and refrigerator.

Unit IX: Behaviour of Perfect Gases and Kinetic Theory of Gases 08 Periods

Chapter–13: Kinetic Theory Equation of state of a perfect gas, work done in compressing a gas. Kinetic theory of gases - assumptions, concept of pressure. Kinetic interpretation of temperature; rms speed of gas molecules; degrees of freedom, law of equi-partition of energy (statement only) and application to specific heat capacities of gases; concept of mean free path, Avogadro's number.

Unit X: Mechanical Waves and Ray Optics 16 Periods

Chapter–14: Oscillations and Waves Periodic motion - time period, frequency, displacement as a function of time, periodic functions. Simple harmonic motion (S.H.M) and its equation; phase; oscillations of a loaded spring-restoring force and force constant; energy in S.H.M. Kinetic and potential energies; simple pendulum derivation of expression for its time period. Free, forced and damped oscillations (qualitative ideas only), resonance. Wave motion: Transverse and longitudinal waves, speed of wave motion, displacement relation for a progressive wave, principle of superposition of waves, reflection of waves, standing waves in strings and organ pipes, fundamental mode and harmonics, Beats, Doppler effect. Chapter–15: RAY OPTICS 18 Periods Ray Optics: Reflection of light, spherical mirrors, mirror formula, refraction of light, total internal reflection and its applications, optical fibres, refraction at spherical surfaces, lenses, thin lens formula, lensmaker's formula, magnification, power of a lens, combination of thin lenses in contact, refraction and dispersion of light through a prism. Scattering of light - blue colour of sky and reddish apprearance of the sun at sunrise and sunset. Optical instruments: Microscopes and astronomical telescopes (reflecting and refracting) and their magnifying powers. The record, to be submitted by the students, at the time of their annual examination, has to include: Record of at least 15 Experiments , to be performed by the students. Record of at least 5 Activities , to be demonstrated by the teachers. Report of the project to be carried out by the students.

Activities (for the purpose of demonstration only) 1. To make a paper scale of given least count, e.g., 0.2cm, 0.5 cm 2. To determine mass of a given body using a metre scale by principle of moments 3. To plot a graph for a given set of data, with proper choice of scales and error bars 4. To measure the force of limiting friction for rolling of a roller on a horizontal plane 5. To study the variation in range of a projectile with angle of projection 6. To study the conservation of energy of a ball rolling down on an inclined plane (using a double inclined plane) 7. To study dissipation of energy of a simple pendulum by plotting a graph between square of amplitude & time SECTION–B Experiments 1. To determine Young's modulus of elasticity of the material of a given wire. 2. To determine the surface tension of water by capillary rise method 3. To determine the coefficient of viscosity of a given viscous liquid by measuring terminal velocity of a given spherical body 4. To determine specific heat capacity of a given solid by method of mixtures 5. a) To study the relation between frequency and length of a given wire under constant tension using sonometer b) To study the relation between the length of a given wire and tension for constant frequency using sonometer. 6. To find the speed of sound in air at room temperature using a resonance tube by two resonance positions. 7. To find the value of v for different values of u in case of a concave mirror and to find the focal length. 8. To find the focal length of a convex lens by plotting graphs between u and v or between 1/u and 1/v. 9. To determine angle of minimum deviation for a given prism by plotting a graph between angle of incidence and angle of deviation. 10. To determine refractive index of a glass slab using a travelling microscope. Activities (for the purpose of demonstration only) 1. To observe change of state and plot a cooling curve for molten wax. 2. To observe and explain the effect of heating on a bi-metallic strip. 3. To note the change in level of liquid in a container on heating and interpret the observations. 4. To study the effect of detergent on surface tension of water by observing capillary rise. 5. To study the factors affecting the rate of loss of heat of a liquid. 6. To study the effect of load on depression of a suitably clamped metre scale loaded at (i) its end (ii) in the middle. 7. To observe the decrease in presure with increase in velocity of a fluid. 8. To observe refraction and lateral deviation of a beam of light incident obliquely on a glass slab. 9. To study the nature and size of the image formed by a (i) convex lens, (ii) concave mirror, on a screen by using a candle and a screen (for different distances of the candle from the lens/mirror). 10. To obtain a lens combination with the specified focal length by using two lenses from the given set of lenses.

Question Wise Break Up Type of Question Mark per Question Total No. of Questions Total Marks VSA 1 5 05 SA-I 2 7 14 SA-II 3 12 36 LA 5 3 15 Total 27 70 1. Internal Choice: There is no overall choice in the paper. However, there is an internal choice in one question of 2 marks weightage, one question of 3 marks weightage and all the three questions of 5 marks weightage. 2. The above template is only a sample. Suitable internal variations may be made for generating similar templates keeping the overall weightage to different form of questions and typology of questions same. Read the full article

[anullhypothesis]

Tweeted

"Energy-Dispersive Total-Reflection Resonant Inelastic X-ray Scattering as a Tool for Elemental Speciation in Contaminated Water" https://t.co/mS2kBu8fSF #in

— Mohammad Sharif Khan (@sharifsks) March 6, 2018

[technato]

New Analysis of Lithium-Ion Batteries Shows How to Pack in More Energy

For the first time, scientists have studied the atomic structure of lithium-rich cathodes while they’re charging

Photo-illustration: SLAC National Accelerator Laboratory

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Helvetica; -webkit-text-stroke: #000000} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Helvetica; -webkit-text-stroke: #000000; min-height: 13.0px} span.s1 {font-kerning: none} span.s2 {font-kerning: none; background-color: #fffb01}

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Helvetica; -webkit-text-stroke: #000000} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Helvetica; -webkit-text-stroke: #000000; min-height: 13.0px} span.s1 {font-kerning: none}

If electric vehicles are ever going to outcompete gas-powered ones, batteries must improve. Conventional lithium-ion batteries, the most energy-dense for their weight, can only be charged to about 50 percent of their theoretical capacity. When researchers have tried to pack more lithium into a battery’s electrodes, it hasn’t helped. The electrodes begin to quickly degrade after the first discharge/recharge cycle, and nobody has been able to figure out how to prevent it.

Now there’s a clue. Using a combination of theoretical computer modeling and sophisticated X-ray methods, researchers have for the first time found a relationship between the way atoms rearrange themselves in the electrode when it’s being charged and how electrons are stored in the battery’s atomic and chemical structures. This insight should give battery-makers a blueprint for building lithium-rich electrodes that could dramatically improve battery performance.

At its full potential, a lithium-rich battery could improve the range of today’s electric vehicles by a third or better. A Tesla Model S with the company’s P100D battery pack, for instance, could go from traveling 315 miles (about 500 kilometers) on a single charge to as far as 473 miles. Or the carmaker could keep the range at 315 miles, but lower the price to compete with gas-powered vehicles without a rebate.

“The dream is to make an affordable mass-market electric vehicle that is the same upfront cost as a gasoline equivalent. Then the consumer starts saving gas money from day one, and everyone would switch to electric,” said William Gent, a Ph.D. student of chemistry at Stanford University and the first author on the study, which appears today in Nature Communications.

Gent worked with professor William Chueh, an investigator at Stanford University, along with researchers from the Lawrence Berkeley National Laboratory’s Advanced Light Source, on the project.

Conventional lithium-ion batteries are pretty straightforward, technically speaking. They have two electrodes—a positively charged cathode and a negatively charged anode—with a liquid electrolyte between them. The cathodes are made up of layers of lithium and transition metals, namely nickel, manganese, or cobalt.

When the battery is charged, lithium ions move from the positive electrode, through the liquid electrolyte, and then insert themselves into the material that makes up the negative electrode. The transition metal ions stay put. The same happens for electrons, except they travel across the circuit on their way to the negative electrode. Ions and electrons travel in the opposite direction when the battery is discharged.

“ We’re hoping we can use this understanding to gain better control of these materials and make them more practical.” —William Gent, Stanford University

Lithium-rich batteries replace some of the transition metals in the electrodes with lithium. Although the additional lithium has the potential to increase the cathode’s capacity by 30 to 50 percent, it creates some mysterious voltage behavior. For instance, the average charging voltage is higher than the average discharging voltage, even at low currents. In a perfect battery, said Gent, the voltages would be the same.

Also, the voltage gradually falls after going through cycles of charging and discharging. Electronic devices can’t manage such erratic voltage behavior, said Gent, because the circuits aren’t able to recalibrate on the fly in order to deal with the changes. That’s why lithium-rich electrodes have been so impractical.

In searching for solutions, previous researchers have typically looked at either how the ions rearrange themselves during charge/discharge cycles or how the electrons are stored in the battery’s atomic and chemical structures. Studying both simultaneously has been extremely difficult because it requires advanced analytical techniques to get the best picture, and not many research teams have access to the necessary equipment.

Gent and his colleagues were able to do that. They worked at two facilities that each had very bright, highly sensitive, and finely tuned X-ray sources to develop hypotheses for how the atomic rearrangements might affect the way electrons are stored within the material. They used X-ray diffraction at SLAC’s Stanford Synchrotron Radiation Lightsource to probe changes in the cathode’s atomic and chemical structure as it was being charged and discharged. At Lawrence Berkeley National Laboratory’s Advanced Light Source they used resonant inelastic X-ray scattering to measure the magnetic and electronic properties of the lithium-rich material.

Next, the scientists used computer models to test their hypotheses. They confirmed that when the lithium-rich cathode was charged, the transition metal ions, which normally stay in place in conventional batteries, moved around. They found that this rearrangement drastically impacts the voltage at which the electrons are stored in the cathode. This wouldn’t be so bad if the ions returned to their original location during discharge. But few did. And each time the battery was charged and discharged, the ions moved a little more, which created disorder in the atomic structure and caused the strange voltage behavior.

“We’re hoping we can use this understanding to gain better control of these materials and make them more practical,” said Gent.

He and his colleagues have already begun to test different ways to address the problem. One idea is to prevent the transition metal ions from migrating. Another is to design the structure in a way that makes it easier for the migrating ion to return to its original position.

New Analysis of Lithium-Ion Batteries Shows How to Pack in More Energy syndicated from http://ift.tt/2Bq2FuP