Spin splitting of electron states in lattice-mismatched (110)-oriented quantum wells

TL;DR

This paper investigates how lattice mismatch-induced strain affects spin splitting in (110)-oriented quantum wells, revealing significant contributions from strain to spin-orbit coupling that vary across material systems.

Contribution

It combines envelope function theory and atomistic tight-binding calculations to quantify strain effects on spin splitting in lattice-mismatched quantum wells.

Findings

Strain significantly influences spin splitting in GaAs/AlGaAs quantum wells.

In InGaAs/GaAs structures, strain can dominate and even reverse the sign of spin splitting.

Strain-induced spin-orbit coupling is a major factor in zero-magnetic-field spin splitting.

Abstract

We show that for lattice-mismatched zinc-blende-type (110)-grown quantum wells a significant contribution to the zero-magnetic-field spin splitting of electron subbands comes from strain-induced spin-orbit coupling. Combining envelope function theory and atomistic tight-binding approach we calculate spin-orbit splitting constants for realistic quantum wells. It is found that the strain due to lattice mismatch in conventional GaAs/AlGaAs structures may noticeably modify the spin splitting while in InGaAs/GaAs structures it plays a major role and may even change the sign of the spin splitting constant.