Spin relaxation in (110) and (001) InAs/GaSb superlattices

TL;DR

This study demonstrates a significant enhancement in electron spin relaxation time in (110) InAs/GaSb superlattices compared to (001) structures, with implications for spintronics.

Contribution

It provides experimental and theoretical insights into how interface symmetry affects spin relaxation times in InAs/GaSb superlattices.

Findings

T1 increased by 25 times in (110) superlattices

Suppression of native interface asymmetry enhances T1

Structural inversion asymmetry may limit spin lifetime

Abstract

We report an enhancement of the electron spin relaxation time (T1) in a (110) InAs/GaSb superlattice by more than an order of magnitude (25 times) relative to the corresponding (001) structure. The spin dynamics were measured using polarization sensitive pump probe techniques and a mid-infrared, subpicosecond PPLN OPO. Longer T1 times in (110) superlattices are attributed to the suppression of the native interface asymmetry and bulk inversion asymmetry contributions to the precessional D'yakonov Perel spin relaxation process. Calculations using a nonperturbative 14-band nanostructure model give good agreement with experiment and indicate that possible structural inversion asymmetry contributions to T1 associated with compositional mixing at the superlattice interfaces may limit the observed spin lifetime in (110) superlattices. Our findings have implications for potential spintronics applications using InAs/GaSb heterostructures.