First-Principles Investigations on Structural, Phonon, and Thermodynamic Properties of Cubic

The structural, phonon, and thermodynamic properties of the cubic are investigated from first-principles calculations. The calculated lattice parameters, bulk modulus, and phonon dispersion curves are in agreement with available experimental data and other calculations. It is shown that the local density approximation (LDA)+ method is more suitable for describing the properties of compared with the LDA method. The pressure and temperature dependences of the specific heat, Debye temperature, and the thermal expansion coefficient are successfully obtained from the Debye-Gruneisen model by combining with the phonon density of states.