Spin-orbit splittings in AlN, GaN and InN

We have calculated the spin-orbit splittings of the top valence bands of Al N, GaN and InN crystallized in the zinc blende structure, using the LMTO-LD A method. Because of the large differences in the atomic splittings of cati ons and anions, and the core d levels of Ga and In, these materials are ide al to investigate anomalies in the valence band splittings. We have obtaine d strong deviations from the Delta (1) similar or equal to (2/3)Delta (0) r ule and extremely anomalous dependences of Delta (1) and Delta (0) on volum e for GaN and InN. Such effects should also appear in the wurtzite counterp arts of these nitride semiconductors. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.