Transition phase and thermodynamic properties of PtC from first-principles calculations

The transition phase of PtC from zincblende (ZB) structure to rocksalt (RS) structure is investigated by ab initio plane-wave pseudopotential density functional theory; the thermodynamic properties of the ZB and RS structures under high pressure and temperature are obtained through the quasi-harmonic Debye model. The transition phase from ZB structure to RS structure occurs at the pressure of 51.7 GPa, which agrees well with other calculated values. Moreover, the dependences of the relative volume V/V0V/V0 on the pressure PP, the Debye temperature ΘΘ and heat capacity CVCV on the pressure PP, together with the heat capacity CVCV on the temperature TT are also successfully obtained.