Transport through a band insulator with Rashba spin-orbit coupling: metal-insulator transition and spin-filtering effects

TL;DR

This paper investigates how Rashba spin-orbit coupling influences transport in a one-dimensional band insulator, revealing a spin-filtering effect and a transition from metal to insulator under magnetic fields.

Contribution

It demonstrates the impact of Rashba spin-orbit coupling on spin-filtering and metal-insulator transition in a 1D band insulator with magnetic field.

Findings

Complete spin-filtering effect without spin-orbit coupling.

Transition from metallic to insulating behavior with increasing magnetic field.

Oscillations of spin currents with channel length.

Abstract

We calculate the current-voltage characteristic of a one-dimensional band insulator with magnetic field and Rashba spin-orbit coupling which is connected to nonmagnetic leads. Without spin-orbit coupling we find a complete spin-filtering effect, meaning that the electric transport occurs in one spin channel only. For a large magnetic field which closes the band gap, we show that spin-orbit coupling leads to a transition from metallic to insulating behavior. The oscillations of the different spin-components of the current with the length of the transport channel are studied as well.