Spin states in InAs/AlSb/GaSb semiconductor quantum wells

TL;DR

This paper theoretically studies spin states in InAs/AlSb/GaSb quantum wells, revealing complex behaviors due to electron-hole hybridization and demonstrating how barrier thickness can tune spin properties.

Contribution

It provides a self-consistent theoretical analysis of spin states in InAs/AlSb/GaSb quantum wells, highlighting differences from Rashba models and the impact of barrier engineering.

Findings

Spin states differ from Rashba model predictions due to hybridization.

Oscillating Rashba spin-splitting in the lowest conduction subband.

Spin relaxation time peaks with increasing Fermi wavevector.

Abstract

We investigate theoretically the spin states in InAs/AlSb/GaSb broken-gap quantum wells by solving the Kane model and the Poisson equation self-consistently. The spin states in InAs/AlSb/GaSb quantum wells are quite different from those obtained by the single-band Rashba model due to the electron-hole hybridization. The Rashba spin-splitting of the lowest conduction subband shows an oscillating behavior. The D'yakonov-Perel' spin relaxation time shows several peaks with increasing the Fermi wavevector. By inserting an AlSb barrier between the InAs and GaSb layers, the hybridization can be greatly reduced. Consequently, the spin orientation, the spin splitting, and the D'yakonov-Perel' spin relaxation time can be tuned significantly by changing the thickness of the AlSb barrier.