Picosecond spin relaxation of acceptor-bound exciton in wurtzite GaN

Abstract

The spin relaxation process of acceptor-bound excitons in wurtzite GaN is observed by spin-dependent pump and probe reflectance measurement with subpicosecond time resolution. The time evolutions measured at 15–50K have a single exponential component corresponding to the electron spin relaxation time of 1.40–1.14ps. The spin relaxation time is found to be proportional to T−0.175, where T is the temperature. This weak temperature dependence indicates that the main spin relaxation mechanism is the Bir-Aronov-Pikus process [Sov. Phys. JETP 42, 705 (1976)].