First Principles Investigation On The Electronic Structure Of MgZnO And The Hydrostatic Pressure Induced Phase Transition In ZnO

In this work,we used the first principles methods to reveal the effects of Mg doping on the electronic structure of ZnO and the hydrostatic pressure induced phase transition in ZnO. All the calculations were carried out using the CASTEP module in the Materials Studio package.LDA approximation,plane-wave basis and super-soft pseudo potential were adopted and the size of the super cell was 2×2×1.After geometrical optimization of super cells containing different number of Mg atoms,the lattice relaxation was obtained and the electronic structure of MgZnO was calculated,the shift of the bottom of conduction band and the top of the valence band was monitored.The results showed that Mg doping caused large relaxation,the bottom of the conduction band was shifted to higher energy side whereas the top of the valence band remained un-shifted.Under LDA approximation,the crystal structure of wurtzite and rocksalt ZnO under different hydrostatic pressure were optimized,the free-energy versus cell volume curve were calculated, and the critical pressure of the phase transition between wurtzite and rocksalt ZnO was obtained.