Electron spin relaxation in GaAs$_{1-x}$Bi$_x$: Effects of spin-orbit tuning by Bi incorporation

TL;DR

This study investigates how bismuth incorporation in GaAs affects electron spin relaxation, revealing a significant decrease in relaxation time due to altered spin-orbit interaction, with implications for spintronic applications.

Contribution

It provides a microscopic analysis of spin relaxation in GaAsBi, highlighting the role of Bi in modifying spin-orbit coupling and relaxation mechanisms across different compositions.

Findings

Bi decreases spin relaxation time via spin-orbit modification

Spin relaxation behavior in GaAsBi resembles GaAs

Bir-Aronov-Pikus mechanism is negligible in intrinsic samples

Abstract

The electron spin relaxation in $n$-type and intrinsic GaAs$_{1-x}$Bi$_x$ with Bi composition $0\le x \le 0.1$ is investigated from the microscopic kinetic spin Bloch equation approach. The incorporation of Bi is shown to markedly decrease the spin relaxation time as a consequence of the modification of the spin-orbit interaction. We demonstrate that the density and temperature dependences of spin relaxation time in GaAs$_{1-x}$Bi$_x$ resemble the ones in GaAs. Meanwhile, the Bir-Aronov-Pikus mechanism is found to be negligible compared to the D'yakonov-Perel' mechanism in intrinsic sample. Due to the absence of direct measurement of the electron effective mass in the whole compositional range under investigation, we further explore the effect of a possible variation of electron effective mass on the electron spin relaxation.