Structural,mechanical, thermodynamics properties and phase transition of FeVSb

The structural, mechanical, thermodynamics properties and phase transition of FeVSb are investigated extensively using the first principle calculations and the quasi-harmonic Debye model. From the calculated elastic constants of cubic FeVSb, some other mechanical quantities, such as bulk modulus and Poisson's ratio, are drawn. Surprisingly, it is found that almost all these mechanical quantities are larger than those of CoVSb (Bo Kong et al., J. Alloys Compd. 509 (2011) 2611); the obtained corresponding transition pressure from fcc to hcp is also larger than that of CoVSb. For these distinctions, their complete different electronic and magnetic behaviors in their cubic structures may be responsible. However, in their hexagonal structures, atomic configurations are similar in terms of the analysis of both the ground-state structure and enthalpy–pressure curves. It is also shown that the elastic instability of cubic FeVSb does not appear with pressure up to 120 GPa and should not be a reason for the pressure-induced phase transition. In addition, heat capacity, Debye temperatures, and so on are obtained successfully for cubic FeVSb under the quasi-harmonic Debye model. Furthermore, we attempt to explore the phase diagram of FeVSb with the model.