Demonstration of Rashba spin splitting in GaN-based heterostructures
  The circular photogalvanic effect (CPGE), induced by infrared radiation, has been observed in (0001)-oriented GaN quantum well (QW) structures. The photocurrent changes sign upon reversing the radiation helicity demonstrating the existence of spin-splitting of the conduction band in k-space in this type of materials. The observation suggests the presence of a sizeable Rashba type of spin-splitting, caused by the built-in asymmetry at the AlGaN/GaN interface. 
W. Weber, S.D. Ganichev, Z.D. Kvon, V.V. Bel'kov, L.E. Golub, S.N.   Danilov, D. Weiss, W. Prettl, Hyun-Ick Cho and Jung-Hee Lee