Structural, mechanical and electronic properties of ZnTe polymorphs under pressure

We have performed first principles calculations based on density functional theory (DFT) to study the structural, mechanical and electronic properties, and pressure-induced phase transition behavior of ZnTe. The generalized gradient approximation is employed together with the projector augmented wave potentials to describe the electron-ion interaction. We consider zinc blende (B3) structure as the ambient pressure phase, the cinnabar (B3), Cmcm (B33) and rocksalt (B1) structures as candidates for the high pressure phases. The calculated structural properties are in good agreement with the experiments and earlier ab initio predictions, as is the transition pressure between them. We determine the sequence of the structural phase transition of ZnTe as B3 -> B9 -> B33, which agrees well with the experiments. The pressure dependence of the elastic constants and the electronic energy band gap of both the ambient and high pressure structures are reported. Tetragonal shear elastic constant C' takes very small value in the parent phase, indicating the elastic instability resulting in phase transition to the high pressure structure. The obtained electronic results show that zinc blende structure is the direct energy band gap semiconductor at Gamma point, while the cinnabar structure has indirect energy band gap along the symmetry of Gamma -> K and Cmcm phase displays the metallic behavior. (C) 2012 Elsevier B. V. All rights reserved.