Strain induced change of band structure and electron effective mass in wurtzite ZnO: A first-principles study

The first-principles hybrid density functional theory is applied to the contrastive investigation on the structural and electronic properties of wurtzite ZnO under hydrostatic strain and uniaxial strain along c axial, and the effect of strain on electron effective mass. It is observed that the structural transformation of the wurtzite ZnO occurs under tensile hydrostatic strain and compressive uniaxial strain. The transformation of ZnO from wurtzite phase to graphitelike phase is accompanied by the transition from a direct to indirect band gap. The deformation potentials that quantify the changes of band gap with strain are also reported. When the hydrostatic strain changes from compression to tension, the electron effective masses at Γ point in Σ, T and Δ directions, and average electron effective mass decrease linearly. For the uniaxial strain, the changes of electron effective mass are dissimilar to the hydrostatic results.