Ab-initio electronic structure calculations and properties of [SixSn1 − x]3N4 ternary nitrides

Abstract We carry out ab initio electronic structure calculations of (Si x Sn 1 − x ) 3 N 4 using density functional theory with projector augmented-wave potentials under the generalized gradient approximation. We find that the energetically favorable structure of Sn 3 N 4 is the face-centered cubic spinel structure, followed by the hexagonal structure which has energy band gaps of 1.85 eV and 1.44 eV respectively. The (Si x Sn 1 − x ) 3 N 4 ternary compound can exhibit both cubic and hexagonal crystal structures over the full range of x. However, the cubic structure is found to be energetically favorable for x  x Sn 1 − x ) 3 N 4 dominates. The energy band gap can be tuned continuously from 1.44 eV up to 5.8 eV in the case of the hexagonal crystal structure of (Si x Sn 1 − x ) 3 N 4 and from 1.85 eV to 4.82 eV in the case of cubic (Si x Sn 1 − x ) 3 N 4 . Nevertheless the energy gap of (Si x Sn 1 − x ) 3 N 4 is direct only for x