Elastic properties and pressure induced transitions of ZnO polymorphs from first-principle calculations

Structural and mechanical properties of ZnO in four different phases, namely, B4 (wurtzite), B3 (zinc-blende), B2 (CsCl) and B1 (rocksalt) are determined using ab initio density functional theory (DFT) calculations. The equations of state for these structures are used in determining the transition pressures from wurtzite to zinc-blende, from wurtzite to rocksalt and zinc-blende to rocksalt structures were also determined. In particular, we report the computed anisotropic elastic properties under high pressures for the phases of B3 and B1 of ZnO. Our results for structural and mechanical properties of ZnO in four phases and the predicted values of the phase transitions for B4 → B3, B4 → B1 and B3 → B1 are compared with the available experimental and theoretical values. It is shown that the results determined in this study are compatible with the experimental and other theoretical calculations.