Picosecond spin relaxation of acceptor-bound exciton in wurtzite GaN

Kazuyoshi Taniguchi, Takako Chinone, Ji-Hao Liang, Masataka Kajikawa, and Naochika Horio Stanley Electric Company, Ltd., Edanishi 1-3-1, Aoba, Yokohama 225-0014, Japan 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 15-50 K have a single exponential component corresponding to spin relaxation times of 1.40 - 1.14 ps. The spin relaxation time, s, is found to be proportional to T-0.175, where T is the temperature. This temperature dependence is quite weak compared with that of A-band free excitons showing s T-1.41 at 150 - 225K.