Mechanical control of spin-orbit splitting in GaAs and InGaAs epilayers

TL;DR

This study demonstrates how mechanical strain influences spin-orbit splitting in GaAs and InGaAs epilayers, using time-resolved Kerr rotation spectroscopy to quantify the effects and establish a linear relationship with applied tension and voltage.

Contribution

It introduces a method to control and measure spin-orbit splitting via mechanical strain in semiconductor epilayers, linking strain to spin splitting energies.

Findings

Spin splitting increases linearly with applied tension.

Voltage also affects the magnitude of spin splitting.

A strain-drift diffusion model correlates strain with spin-orbit splitting.

Abstract

Time-resolved Kerr rotation spectroscopy as a function of pump-probe distance, voltage and magnetic field is used to measure the momentum-dependent spin splitting energies in GaAs and InGaAs epilayers. The strain of the samples can be reproducibly controlled in the cryostat using three- and four-point bending applied with a mechanical vise. We find that the magnitude of the spin splitting increases linearly with applied tension and voltage. A strain-drift diffusion model is used to relate the magnitude of the measured spin-orbit splitting to the amount of strain in the sample.