Theoretical investigation on compressibility, electronic and thermodynamic properties of single crystal PtAs2 under high pressure

A theoretical investigation on compressibility, electronic and thermodynamic properties of recently reported semiconductor PtAs2 at high pressure and high temperature was performed by employing the first-principles calculations based on the density functional theory. The calculated equilibrium crystal parameter and normalized volume dependence of the resulting pressure are all in excellent agreement with experimental data. The compressibility and elastic anisotropy of the PtAs2 are also explored in the pressure range of 0–40 GPa. The derived bulk moduli for PtAs2 by using elastic constants and different EOS fittings are all much smaller than the corresponding experimental data, suggesting that PtAs2 may be not a highly incompressible material as the recent experiment reported. Detailed analyses of the electronic structures under pressure reveal that the indirect energy gap of PtAs2 increases with pressure. By using quasi-harmonic Debye model, the Debye temperature, Grüneisen parameter, heat capacity, and expansion coefficient of PtAs2 are successfully obtained under high pressure and high temperature in the present work.