Title: Monte-Carlo modeling of phonon thermal transport using DFT-based anisotropic dispersion relations over the full Brillouin zone

Abstract

In this work, we present a Monte Carlo (MC) approach to solve the phonon Boltzmann transport equation (BTE) in which the anisotropic phonon dispersion relations over the full Brillouin zone (BZ) are used. In this approach, the discretization of the BZ used to compute the phonon relaxation time places constraints on the direction of scattered phonons in the real-space simulation domain. The phonon dispersion and phonon relaxation times are calculated using the density functional theory (DFT) approach. The modified MC approach is validated by a close examination of its ability to simulate phonon transport in both the ballistic and diffusive regimes for multiple materials including GaAs, InAs, ThO₂, and α-U. In doing so, the phonon thermal conductivities from 100 K to 1000 K are calculated and compared with traditional non-transport solution of the phonon BTE. It is found that the phonon thermal conductivities of α-U and ThO₂ obtained from MC simulations using isotropic dispersion are larger than the values obtained using anisotropic phonon dispersion relations over the full BZ. The effect of phonon-defect scattering on the thermal conductivity of ThO₂ is also studied as an application of the current MC approach and found to agree with previously computed values inmore » the literature. The MC solver developed here has been parallelized as a step to demonstrate its potential to solving computationally intensive phonon thermal transport problems at the mesoscale.« less

Authors:

Peng, Jie ^[1]; Deskins, W. Ryan ^[1]; El-Azab, Anter ^[1]

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1. Purdue Univ., West Lafayette, IN (United States)

Publication Date:

Sat May 21 00:00:00 EDT 2022

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Thermal Energy Transport under Irradiation (TETI)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1981585

Resource Type:

Accepted Manuscript

Journal Name:

Computational Materials Science

Additional Journal Information:

Journal Volume: 211; Journal Issue: C; Journal ID: ISSN 0927-0256

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; materials science; Monte Carlo method; Boltzmann transport equation; anisotropic phonon dispersion; density functional theory; defects