Magnetotunnelling in resonant tunnelling structures with spin-orbit interaction

TL;DR

This paper models magnetotunnelling in resonant tunnelling structures with spin-orbit interaction, revealing effects of Rashba spin-orbit coupling and predicting significant spin polarization under magnetic fields.

Contribution

It introduces a nonequilibrium Green's function model to analyze spin-dependent tunnelling phenomena, including electron-phonon interaction, interface roughness, and Rashba effects.

Findings

Satellite peaks match experimental data qualitatively.

Spin polarization exceeds 10% at magnetic fields above 2 Tesla.

Rashba effect causes a beating pattern in the density of states, but minimally impacts tunnelling current.

Abstract

Magnetotunnelling spectroscopy of resonant tunnelling structures provides information on the nature of the two-dimensional electron gas in the well. We describe a model based on nonequilibrium Green's functions that allows for a comprehensive study of the density of states, tunnelling currents and current spin polarization. The investigated effects include the electron-phonon interaction, interface roughness scattering, Zeeman effect and the Rashba spin-orbit interaction. A qualitative agreement with experimental data is found regarding the satellite peaks. The spin polarization is predicted to be larger than ten percent for magnetic fields above 2 Tesla and having a structure even at the satellite peaks. The Rashba effect is confirmed to be observable as a beating pattern in the density of states but found to be too small to affect the tunnelling current.