Assessing exchange-correlation functionals for elasticity and thermodynamics of alpha-ZrW2O8: A density functional perturbation theory study

摘要

Elastic and thermodynamic properties of negative thermal expansion (NTE) alpha-ZrW2O8 have been calculated using PBEsol and PBE exchange-correlation functionals within the framework of density functional perturbation theory (DFPT). Measured elastic constants are reproduced within similar to 2% with PBEsol and similar to 6% with PBE. The thermal evolution of the Gruneisen parameter computed within the quasi-harmonic approximation exhibits negative values below the Debye temperature, consistent with observation. The standard molar heat capacity is predicted to be C-P(0) = 192.2 and 193.8 J mol(-1) K-1 with PBEsol and PBE, respectively. These results suggest superior accuracy of DFPT/PBEsol for studying the lattice dynamics, elasticity and thermodynamics of NTE materials. (C) 2018 Elsevier B.V. All rights reserved.