Spin current density functional theory of Weyl semimetals

Abstract

Weyl fermions are massless solutions of the Dirac equation, described by two-component complex spinors. Such elusive objects emerge as quasiparticles in the so-called Weyl semimetals (WSM). The authors discuss the generalization of the standard one-component density functional theory to a two-component approach (the spin-current density functional theory) as well as its application to the practical quantum-mechanical description of WSMs through a self-consistent treatment of the spin-orbit coupling and nonlocal Fock exchange. In particular, the authors demonstrate the key role played by spin-current densities in the characterization of Weyl nodes in TaAs.