Mapping spin-orbit splitting in strained InGaAs epilayers

TL;DR

This study uses Faraday rotation spectroscopy to measure how strain affects spin splitting in InGaAs epilayers, revealing anisotropic effects and comparing results with theoretical models.

Contribution

It provides detailed measurements of spin splitting in strained InGaAs, distinguishing isotropic and anisotropic components related to strain directions.

Findings

Spin splitting varies with electron drift velocity and strain orientation.

Anisotropic and isotropic magnetic fields are separated and characterized.

Results align with and extend previous theoretical predictions.

Abstract

Time- and spatially-resolved Faraday rotation spectroscopy is used to measure the magnitude and direction of the momentum-dependent spin splitting in strained InGaAs epilayers. The epilayers are lattice-matched to the GaAs substrate and designed to reduce inhomogeneous effects related to strain relaxation. Measurements of momentum-dependent spin splitting as a function of electron spin drift velocity along [100], [010], [110] and [1$\overline{1}$0] directions enable separation of isotropic and anisotropic effective magnetic fields that arise from uniaxial and biaxial strain along $\langle$110$\rangle$. We relate our findings to previous measurements and theoretical predictions of spin splitting for inversion symmetry breaking in bulk strained semiconductors.