Quasiharmonic vibrational properties of tinisn from ab initio phonons

Daehyun Wee, Boris Kozinsky, Barbara Pavan, Marco Fornari

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

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.

Original languageEnglish
Pages (from-to)977-983
Number of pages7
JournalJournal of Electronic Materials
Volume41
Issue number6
DOIs
StatePublished - Jun 2012

Keywords

  • Thermoelectrics
  • half-Heusler compound
  • thermal conductivity
  • thermal expansion

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