Ab initio calculations of structural properties of ScxGa1-xN

We present first-principles total energy calculations within the full-potential linearized augmented plane wave method in the gradient-generalized approximation so as to study the structural properties of ScxGa1-xN in zinc blende, NaCl and CsCl-like structures at normal, and under hydrostatic pressure. Our results showed generally reasonable agreement with the available experimental and theoretical findings. It is found that with scandium concentrations of 0%, 25%, and 50%, zinc blende is the most stable configuration among those considered here, whereas for scandium concentrations of 75% and 100%, rocksalt is the most stable one. Deviation of the lattice constants from Vegard's law is shown to be alloy composition dependent. We provide analytical expressions for the scandium concentration dependence of the lattice constant, bulk modulus, and its pressure derivative. (c) 2008 American Institute of Physics.