9-13 July 2012
Structural and Electronic Properties of ZnO: a hybrid density functional study
Presented by Mr. Mahlaga MOLEPO on 13 Jul 2012 from 12:00 to 12:20
Type: Oral Presentation
Track: Track G - Theoretical and Computational Physics
We present results of ab initio total energy calculations for the bulk structural phases of ZnO under high pressure. The study is based on density functional theory (DFT), using the projector augmented wave (PAW) potentials, and the Heyd-Scuseria-Ernzerhof (HSE06) screened hybrid density functional for electron exchange and correlation. Apart from the ambient pressure B4 (hexagonal wurtzite) structure, and the B3 (cubic zinc blende) structures, a tetragonal B10 (PbO-type) structure is predicted to be an intermediate phase (at about 273 GPa) between the high-pressure B1 (cubic rocksalt) and B2 (cubic CsCl) phases. It is shown that the HSE functional yields lattice constants and bulk moduli in better agreement with experiment than the widely used conventional exchange correlation functionals. Most importantly, HSE band structure calculations result in significantly improved semiconducting energy band gaps for ZnO over the widely used semilocal functionals, thus improving agreement with experiments.
Prof. Daniel P. Joubert Daniel.Joubert2@wits.ac.za University of the Witwatersrand