Advanced properties of mesoscopic and spatially inhomogeneous electronic matter
Abstract
t is now possible to control and manipulate matter at extremely small scales. Therefore, new physical problems regarding the behavior of spatially inhomogeneous many-particle systems can be studied. This project aims to investigate several two-dimensional (2D), or quasi-2D, and 3D spatially-inhomogeneous systems. We aim to explore several specific systems. In particular, we are interested in the properties of the electronic systems with imperfect nesting of the Fermi surface. Recently, in the models of this type, we put forward theoretical mechanism stabilizing a new class of many body states. We referred to such states as Òspin-valley half-metals.Ó This state is a generalization of the well-known half-metals. The materials realizing the new state may be useful for the so-called spin-valleytronics. The proposed microscopic mechanism differs significantly from the usual half-metal model based on a strong electron-electron interaction. This might give rise to a new direction in search for ÒnonmetallicÓ half-metals, i.e., those that do not contain atoms of transition metals. These would come in handy in those applications, for which non-toxicity is important, for example, biocompatible and implantable devices and systems. We also plan to study inhomogeneous phases driven by imperfect Fermi surface nesting. In general, inhomogeneous phases occur in strongly correlated systems, e.g., the existence of stripes in high-Tc superconductors. Usually, systems with imperfect nesting demonstrate different kinds of instabilities (e.g., stripes, phase separation, incommensurate spin and charge density waves) even in a weak-coupling regime. Which instability is dominant depends on the concentration of impurities, long-range Coulomb force, and applied fields. We plan to study the stability of different phases, in particular the superconducting phase and different inhomogeneous phases, in systems with imperfect nesting. We expect that the obtained results will be of interest for the study of pnictide superconductors, bilayer graphene, and borides of rare-earth metals. In addition to a purely fundamental significance, the planned study may be of consequence for applications: control over formation of inhomogeneities opens a new route to microfabrication of quantum dots, channels and other nanostructures. We plan to continue our previous investigations of the electronic properties of graphene and Weyl semimetals in strong electromagnetic fields. We also expect to study the ÒhotÓ problem of electron transport in Weyl semimetals, taking into account different kinds of impurity potentials and the anisotropy of the Dirac cone. We plan to study Majorana fermions in topological superconductors. The methods to create and manipulate these fermions in the bulk topological superconductors and in the proximity-induced superconducting layers in the superconductor/topological insulator heterostructures are hotly debated recently. We intend to investigate the stability of the Majorana states in topological superconductors. We also plan to consider the possibility to control and move Majorana fermions using magnetic fields in such systems.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 20, 2018
- Source ID
- W911NF1810358
Entities
People
- Franco Nori
Organizations
- Army Contracting Command
- RIKEN Brain Science Institute
- United States Army