First-principles calculations for electronic, optical and thermodynamic properties of ZnS

The electronic, optical and thermodynamic properties of ZnS in thezinc-blende (ZB) and wurtzite (WZ) structures are investigated byusing the plane-wave pseudopotential density functional theory(DFT). The results obtained are consistent with othertheoretical results and the available experimental data. When thepressures are above 20.5 and 27,GPa, the ZB-ZnS and the WZ-ZnS areconverted into indirect gap semiconductors, respectively. Thecritical point structure of the frequency-dependent complexdielectric function is investigated and analysed to identify theoptical transitions. Moreover, the values of heat capacity $C_{V}$and Debye temperature {$Th$} at different pressures anddifferent temperatures are also obtained successfully.