Comparing the effects of uniaxial and biaxial strains on the structural stability and electronic structure in wurtzite ZnS

摘要

Structural stability and electronic structure of wurtzite ZnS under uniaxial and biaxial strains are systematically studied using the HSE hybrid functional. The two types of strain display the markedly different influences on the structural and electronic properties: (Ⅰ) The newly predicted graphite-like phase is observed at large compressive uniaxial strains, not at large tensile biaxial strains, which is attributed to the different elastic responses to uniaxial and biaxial strains. (Ⅱ) The direct band structures are obtained in wurtzite ZnS under uniaxial and biaxial strains, whereas the indirect band gaps are only observed in graphite-like ZnS under large uniaxial strain. Our results are different from the widely accepted conclusion but are in good agreement with the available experimental data.