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 $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{8}{\mathrm{cm}}^{\mathrm{\ensuremath{-}}2},$ this coherence yields spin lifetimes of \ensuremath{\sim}20 ns at $T=5\mathrm{K},$ 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.