First principles investigation of thermal properties of thorium mononitride

[摘要] We compared the heat capacity and thermal conductivity of ThN calculated using ab initio methods versus recently published porosity-free experimental data. The experiments provided only a cumulative contribution from phonons and electrons; the problem thus presented was how to distinguish between each contribution and the new correlations were developed. We used the generalized gradient approximation (GGA) of the Perdew, Burke, and Ernzerhof functional, as implemented in Quantum ESPRESSO (QE) and associated code, ShengBTE. We noted a lower contribution from the optical phonons to the lattice thermal conductivity at 300 K (0.95 W m(-1) K-1), than previously determined for UN (4.33 W m(-1) K-1), ThO2 (4.17 W m(-1) K-1) and experimentally for Urania (similar to 4 W m(-1) K-1). However the evaluated here only similar to 5% optical phonon contribution is comparable to 6% found for ThC. The calculated heat capacity is in good agreement with experiment. The electronic thermal conductivity, evaluated from resistivity, combined with the lattice-assisted contribution, calculated by ShengBTE, also agrees with the experiment. (C) 2021 Elsevier B.V. All rights reserved.

[发布日期] 2021-10-25

[关键词] ThN;Thermal conductivity;Heat capacity;Electronic structure;Phonon's dispersion relation;Quantum ESPRESSO;ShengBTE