Spin coherence and dephasing in GaN

Time-resolved Faraday rotation is used to measure electron spin coherence in n-type GaN epilayers. Despite densities of charged threading dislocations of ~5×10⁸cm^-2, this coherence yields spin lifetimes of {~}20 ns at T=5K, 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.