Stability of wurtzite and rocksalt MgxZn1-xO alloys

Abstract

We investigate the stability of wurtzite and rocksalt MgxZn1-xO random alloys using a first principles pseudopotential method within the local-density-functional approximation. From the calculated cohesive energies for MgxZn1-xO alloys in both the wurtzite and rocksalt structures we find that the wurtzite phase is only stable for x < 0.375. We propose that the solubility limit of Mg in wurtzite MgxZn1-x alloys is about x = 0.375, close to the experimentally measured value of x = 0.33. The band gap (E-gap) is found to increase almost linearly with the Mg composition for x < 0.5, with the coefficient of dE(gap)/dx = 2 eV.