Robust half-metallicity of AlCoN and AlNiN

Theoretical investigations of Al1-xCoxN and Al1-xNixN (x = 0.25) in the zinc blende phase are presented. The robustness of half metallicity of these compounds with correlation to their lattice compressions is discussed. The results show that both compounds retain their half-metallic nature (conductor for spin up state and semiconductor for spin down state) with their lattice compressions up to certain critical lattice constants. Abrupt changes in the electronic and magnetic properties are observed at these robust transition lattice constants (RTLCs). These compounds lose their integer magnetic moments of 4 mu beta for Al1-xCoxN and 3 mu beta for Al1-xNixN at RTLCs. The calculated RTLC for Al0.75Co0.25N is 4.4 angstrom and for Al0.75Ni0.25N is 4.2 angstrom. The possible compression in the lattice constants from their relaxed states while maintaining their half-metallic nature is up to 4% for both compounds. (C) 2012 Wiley Periodicals, Inc.