Static Electrons in Flat-Band Nonequilibrium Superconductors
Get link
Facebook
X
Pinterest
Email
Other Apps
Single electrons stay stationary in superconductors with “flat-band” electronic structures, which could lead to low-energy-consumption devices made from such materials.
In 2018, researchers discovered that two layers of graphene, stacked and twisted at a specific angle, could exhibit superconductivity. Theorists have determined that the electronic structure of such a twisted material approximately resembles a “flat band,” which means that the energy of the materials’ free electrons remains constant regardless of the electrons’ momenta. This phenomenon inspired a flurry of work on systems that exhibit flat-band superconductivity. However, most of the research has focused on how such systems behave under equilibrium conditions. Now Päivi Törmä of Aalto University in Finland and her colleagues have probed the behavior of superconducting flat-band systems under nonequilibrium conditions . The findings could help in the design of superconducting devices with low energy consumption.
Törmä and her colleagues considered an idealized flat-band material subjected to an applied voltage, making it a nonequilibrium system. Their predictions indicate that in this nonequilibrium system the paired and unpaired electrons follow the same behavior patterns as those in an equilibrium system: unpaired electrons form stationary quasiparticles and paired electrons flow with zero resistance. Additionally, in both types of systems the flat band helps the electrons form the bound pairs required for superconductivity.
Törmä says that the team’s results show that flat-band materials offer a potential advantage over superconductors that contain moving quasiparticles. Such quasiparticles dissipate energy in an alternating current, increasing the system’s energy consumption. In future work, the researchers plan to extend this study, which looks at an idealized material, to realistic materials and to collaborate with experimentalists to test their model’s predictions.
In their theoretical work, Dr. Diddo Diddens from Helmholtz Institute Münster of Forschungszentrum Jülich and Prof. Andreas Heuer from the Helmholtz Institute Münster and the Institute of Physical Chemistry of the University of Münster investigated the central question of the extent to which ions in liquid electrolytes move statistically correlated, i.e. together, in one direction. With this knowledge, the influence of individual factors, such as ion pairs on conductivity, can be better determined. The detailed results of their study have been published in the Journal of Chemical Physics and on the pre-print server arXiv. It is often assumed that two ions with the same charge avoid each other due to mutual repulsion and thus move in opposite directions. Now, the researchers are able to show that two neighboring ions with the same charge move in the same direction. "This counter-intuitive behavior can be explained by the fact that the electrolyte, as a liquid, is incompressible, ...
A density wave (DW) is a fundamental type of long-range order in quantum matter tied to self-organization into a crystalline structure. Although density waves are seen in a wide range of materials, such as metals, insulators, and superconductors, studying them has proven challenging, particularly when this order (the patterns of the wave’s particles) coexists with other types of organization, such as superfluidity, which allows particles to flow without resistance. Scientists at EPFL have found a new way to create a “density wave” in an atomic gas. The findings could lead to a better understanding of the behavior of quantum matter. Professor Jean-Philippe Brantut at EPFL said, “Cold atomic gases were well known in the past for the ability to ‘program’ the interactions between atoms. Our experiment doubles this ability!” To study this interaction, Brantut, and his colleagues created a “unitary Fermi gas,” a thin gas of lithium atoms that has been cooled to incredibly low temperatu...
International Conference on Condensed Matter Physics E=mc2 Albert Einstein proposed the most famous formula in physics in a 1905 paper on Special Relativity titled Does the inertia of an object depend upon its energy content? Essentially, the equation says that mass and energy are intimately related. Atom bombs and nuclear reactors are practical examples of the formula working in one direction, turning matter into energy. But until now there has been no way to do the reverse, turn energy into matter. What makes it particularly hard is that c2 term, the speed of light squared. It accounts for the huge amounts of energy released in nuclear reactions, and the huge amount you’d need to inject to turn energy into matter. Previous experiments have always required a little bit of mass, even if it was only an electron’s worth. But scientists at Imperial College London (including a visiting physicist from Germany's Max Planck Institute for Nuclear Physics) think they’ve figured out how to...
Comments
Post a Comment