Calculation of the electronic structure of delafossite AgTaN2 from first principles

Abstract

The electronic structure (band structure, DOS and COHP) of the delafossite nitride AgTaN2 was investigated on the basis of density-functional theory using the generalized-gradient approximation (GGA). AgTaN2 is predicted to be a semiconductor with an indirect band gap. The characters of the top of the valence band and the bottom of the conduction band are attributed to AgN antibonding and TaN antibonding interactions, respectively. These results were compared to the bonding situation in isostructural AgGaO2. With increasing pressure, the electronic structure of AgTaN2 changes. At a pressure of ca. 42 GPa, the indirect band gap should transform into a direct one, and at even higher pressures (above 65 GPa) AgTaN2 should become metallic. © 2011 The Ceramic Society of Japan. All rights reserved.