티스토리 뷰

Wee, D., Kozinsky, B., Pavan, B., and Fornari, M. Quasiharmonic vibrational properties of TiNiSn from ab initio phonons. Journal of Electronic Materials. 2012, Volume 41, Number 6, Pages 977-983. doi:10.1007/s11664-011-1833-4

Abstract

We report an ab initio study of vibrational and thermodynamic properties of
TiNiSn, a half-Heusler alloy that has been investigated in the context of
thermoelectrics, based on density functional theory and density functional
perturbation theory. The quasiharmonic approximation, where the Helmholtz
free energy obtained from phonons of multiple strained structures is fitted to a
model equation of state, is employed to estimate thermodynamic properties.
Good quantitative correspondence is achieved between experimental observations
and our theoretical calculation for various thermodynamic quantities:
lattice parameter, thermal expansion coefficient, and heat capacity. Estimates
of lattice thermal conductivity are also provided by using a semianalytic model
previously proposed in the literature. Though this yields good qualitative
agreement, a more accurate ab initio approach that explicitly includes
anharmonic interactions between atoms should be employed for quantitative
predictions of thermal conductivity.