Anomalous Spin Dephasing in (110) GaAs Quantum Wells: Anisotropy and Intersubband Effects

TL;DR

This paper investigates the anisotropic electron spin decoherence in (110) GaAs quantum wells, revealing a novel intersubband scattering mechanism that explains unexpected spin lifetime behaviors.

Contribution

It introduces a new spin dephasing mechanism based on intersubband scattering, explaining anisotropic and temperature-dependent spin decoherence in (110) GaAs quantum wells.

Findings

Spin lifetime for perpendicular spins is much shorter than along (110).

Spin lifetimes decrease monotonically above certain temperatures.

A new intersubband scattering mechanism explains the anisotropic dephasing.

Abstract

A strong anisotropy of electron spin decoherence is observed in GaAs/(AlGa)As quantum wells grown on (110) oriented substrate. The spin lifetime of spins perpendicular to the growth direction is about one order of magnitude shorter compared to spins along (110). The spin lifetimes of both spin orientations decrease monotonically above a temperature of 80 and 120 K, respectively. The decrease is very surprising for spins along (110) direction and cannot be explained by the usual Dyakonov Perel dephasing mechanism. A novel spin dephasing mechanism is put forward that is based on scattering of electrons between different quantum well subbands.