Rashba coupling and spin switching through surface states of Dirac semimetals

TL;DR

This paper investigates how Rashba spin-orbit coupling affects surface states in Dirac semimetals, revealing controllable spin switching mechanisms with potential spintronic applications.

Contribution

It provides analytical and numerical analysis of Rashba-induced spin rotation and conductance in Dirac semimetals, highlighting robustness against disorder and external control methods.

Findings

Rashba coupling induces significant spin rotation of surface states.

Spin-flip conductance can dominate depending on Hamiltonian parameters.

Spin switching remains robust even with impurities.

Abstract

We study the effect of the Rashba spin-orbit coupling on the Fermi arcs of topological Dirac semimetals. The Rashba coupling is induced by breaking the inversion symmetry at the surface. Remarkably, this coupling could be enhanced by the interaction with the substrate and controlled by an external electric field. We study analytically and numerically the rotation of the spin of the surface states as a function of the electron's momentum and the coupling strength. Furthermore, a detailed analysis of the spin-dependent two-terminal conductance is presented in the clean limit and with the addition of a random distribution of impurities. Depending on the magnitude of the quadratic terms in the Hamiltonian, the spin-flip conductance may become dominant, thus showing the potential of the system for spintronic applications, since the effect is robust even in the presence of disorder.