Improved method of calculating ab initio high-temperature thermodynamic properties with application to ZrC

Andrew Ian Duff, Theresa Davey, Dominique Korbmacher, Albert Glensk, Blazej Grabowski, Jörg Neugebauer, Michael W. Finnis

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)

Abstract

Thermodynamic properties of ZrC are calculated up to the melting point (Tmelt≈3700K), using density functional theory (DFT) to obtain the fully anharmonic vibrational contribution, and including electronic excitations. A significant improvement is found in comparison to results calculated within the quasiharmonic approximation. The calculated thermal expansion is in better agreement with experiment and the heat capacity reproduces rather closely a CALPHAD estimate. The calculations are presented as an application of a development of the upsampled thermodynamic integration using Langevin dynamics (UP-TILD) approach. This development, referred to here as two-stage upsampled thermodynamic integration using Langevin dynamics (TU-TILD), is the inclusion of tailored interatomic potentials to characterize an intermediate reference state of anharmonic vibrations on a two-stage path of thermodynamic integration between the original DFT quasiharmonic free energy and the fully anharmonic DFT free energy. This approach greatly accelerates the convergence of the calculation, giving a factor of improvement in efficiency of ∼50 in the present case compared to the original UP-TILD approach, and it can be applied to a wide range of materials.

Original languageEnglish
Article number214311
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume91
Issue number21
DOIs
Publication statusPublished - 2015 Jun 30
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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