Spin relaxation in sub-monolayer and monolayer InAs structures grown in GaAs matrix

TL;DR

This study investigates electron spin relaxation in InAs/GaAs heterostructures with sub-monolayer and monolayer InAs, revealing enhanced relaxation times in sub-monolayer samples and analyzing the underlying mechanisms affecting spin dynamics.

Contribution

It provides new insights into how sub-monolayer InAs layers influence spin relaxation times and the roles of different mechanisms in spin decoherence.

Findings

Sub-monolayer InAs exhibits significantly longer spin relaxation times.

Spin relaxation is influenced by the D'yakonov-Perel' and Bir-Aronov-Pikus mechanisms.

Spin relaxation times depend strongly on photon-generated carrier density.

Abstract

Electron spin dynamics in InAs/GaAs heterostructures consisting of a single layer of InAs (1/3$\sim$1 monolayer) embeded in (001) and (311)A GaAs matrix was studied by means of time-resolved Kerr rotation spectroscopy. The spin relaxation time of the sub-monolayer InAs samples is significantly enhanced, compared with that of the monolayer InAs sample. We attributed the slowing of the spin relaxation to dimensionally constrained D\textquoteright{}yakonov-Perel\textquoteright{} mechanism in the motional narrowing regime. The electron spin relaxation time and the effective g-factor in sub-monolayer samples were found to be strongly dependent on the photon-generated carrier density. The contribution from both D\textquoteright{}yakonov-Perel\textquoteright{} mechanism and Bir-Aronov-Pikus mechanism were discussed to interpret the temperature dependence of spin decoherence at various carrier densities.