Electric-Field-Induced Resonant Spin Polarization in a Two-Dimensional Electron Gas

TL;DR

This paper investigates how electric fields induce resonant spin polarization in a 2D electron gas with structural inversion asymmetry, revealing conditions for resonance and effects of disorder, with potential for electric control of spin states.

Contribution

It demonstrates the occurrence of electric-field-induced resonant spin polarization near Landau level crossings and analyzes the effects of disorder and temperature on this phenomenon.

Findings

Resonant spin polarization occurs near Landau level crossings.

Resonant peak inversely proportional to electric field at low temperatures.

Disorder suppresses the resonant effect by opening an energy gap.

Abstract

Electric response of spin polarization in two-dimensional electron gas with structural inversion asymmetry subjected to a magnetic field was studied by means of the linear and non-linear theory and numerical simulation with the disorder effect. It was found by Kubo linear reponse theory that an electric resonant response of spin polarization occurs when the Fermi surface is located near the crossing of two Landau levels, which is induced from the competition between the spin-orbit coupling and Zeeman splitting. The scaling behavior was investigated with a simplified two-level model by non-linear method, and the resonant peak value is reciprocally proportional to the electric field at low temperatures and to temperature for finite electric fields. Finally numerical simulation illustrated that impurity potential opens an enegy gap near the resonant point and suppresses the effect gradually with the increasing strength of disorder. This resonant effect may provide an efficient way to control spin polarization by an external electric field.