Spin coherence and dephasing in GaN

Abstract

Time-resolved Faraday rotation is used to measure electron spin coherence in n-type GaN epilayers. Despite densities of charged threading dislocations of $\sim 5\times {10}^8{\mathrm{cm}}^{\mathrm{-}2},$ this coherence yields spin lifetimes of ∼20 ns at $T=5\mathrm{}\mathrm{K},$ and persists to room temperature. Spin dephasing is investigated in the vicinity of the metal-insulator transition. The dependence on both magnetic field and temperature is found to be qualitatively similar to previous studies in n-type GaAs, suggesting a common origin for spin relaxation in these systems.