First-Principles Calculations for Thermodynamic Properties of Perovskite-Type Superconductor MgCNi3

The ground state properties and equation of state of the non-oxide perovskite-type superconductor MgCNi₃ are investigated by first-principles calculations based on the plane-wave basis set with the local density approximation (LDA) as well as the generalized gradient approximation (GGA) for exchange and correlation, which agree well with both theoretical calculations and experiments. Some thermodynamic properties including the heat capacity, the thermal expansion coefficient and the Grüneisen parameter for perovskite structure MgCNi₃ are obtained. The dependences of these thermodynamic properties on pressure and temperature are given for the first time.