Electron spin relaxation in bulk GaAs at room temperature: A Monte Carlo-based quantitative study

The electron spin relaxation time is a critical parameter that directly influences the performance of spintronic devices. We investigate spin relaxation in bulk GaAs at room temperature by combining time-resolved photoluminescence measurements with Monte Carlo simulations incorporating multiple scattering mechanisms. While spin relaxation in this system is predominantly governed by the D'yakonov–Perel mechanism, previous studies have often relied on approximate analytical expressions valid in the motional narrowing regime and employed Dresselhaus coefficients significantly larger than those supported by recent experiments and first-principles calculations. Our simulation framework treats longitudinal optical phonon, acoustic phonon, electron–electron, and electron–hole scattering under the assumption of thermal equilibrium, enabling energy-resolved tracking of spin dynamics with accurate momentum relaxation modeling. Using a Dresselhaus coefficient γD=8.8 eV Å3—consistent with values previously obtained from persistent spin helix experiments and ab initio theory—our simulations quantitatively reproduce the measured spin relaxation time across a wide range of electron densities and capture its experimentally observed nonmonotonic dependence, with a maximum at 2–3×1017 cm−3 arising from the interplay between spin precession and momentum scattering. These results demonstrate that our Monte Carlo-based approach provides a robust and accurate framework for investigating spin relaxation via the D'yakonov–Perel mechanism beyond the limits of conventional analytical approximations, offering valuable insights for the design and optimization of spintronic devices.