Ultrafast Hole-Spin Dynamics in Optically Excited Bulk GaA

TL;DR

This paper investigates ultrafast hole-spin dynamics in bulk GaAs using combined experimental and theoretical approaches, revealing detailed relaxation mechanisms and effects of doping and temperature on spin relaxation times.

Contribution

It provides a comprehensive analysis of hole-spin relaxation in GaAs, integrating experimental data with dynamical Boltzmann-based calculations, and explores effects of doping and temperature.

Findings

Good agreement between experiment and theory for relaxation times

Short-time deviations from exponential decay in spin polarization

Spin-relaxation behavior varies with doping and temperature

Abstract

We present experimental and theoretical results on hole-spin dynamics in bulk GaAs after ultrafast optical excitation. The experimental differential transmission are compared with a dynamical calculation of the momentum-resolved hole distributions, which includes the carrier-carrier, carrier-phonon and carrier-impurity interaction at the level of Boltzmann scattering integrals. We obtain good agreement with the experimentally determined hole-spin relaxation times, but point out that depending on how the spin-polarization dynamics is extracted, deviations from an exponential decay at short times occur. We also study theoretically the behavior of the spin-relaxation for heavily p-doped GaAs at low temperatures.