Thermodynamic properties of OsB under high temperature and high pressure

The energy-volume curves of OsB have been obtained using the first-principles plane-wave ultrasoft-pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA) and local density approximation (LDA). Using the quasi-harmonic Debye model we first analyze the specific heat, the coefficients of thermal expansion as well as the thermodynamic Gruneisen parameter of OsB in a wide temperature range at high pressure. At temperature 300 K, the coefficients of thermal expansion alpha(v) by LDA and GGA calculations are 1.67 x 10(-5) 1/K and 2.01 x 10(-5) 1/K, respectively. The specific heat of OsB at constant pressure (volume) is also calculated. Meanwhile, we find that the Debye temperature of OsB increases monotonically with increasing pressure. The present study leads to a better understanding of how the OsB materials respond to pressure and temperature. (C) 2011 Elsevier B.V. All rights reserved.