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Spectral decomposition of thermal conductivity: Comparing velocity decomposition methods in homogeneous molecular dynamics simulations

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journal contribution
posted on 28.10.2021, 12:19 by Alexander J Gabourie, Zheyong Fan, Tapio Ala-NissilaTapio Ala-Nissila, Eric Pop
The design of applications, especially those based on heterogeneous integration, must rely on detailed knowledge of material properties, such as thermal conductivity (TC). To this end, multiple methods have been developed to study TC as a function of vibrational frequency. Here, we compare three spectral TC methods based on velocity decomposition in homogenous molecular dynamics simulations: Green-Kubo modal analysis (GKMA), the spectral heat current (SHC) method, and a method we propose called homogeneous nonequilibrium modal analysis (HNEMA). First, we derive a convenient per-atom virial expression for systems described by general many-body potentials, enabling compact representations of the heat current, each velocity decomposition method, and other related quantities. Next, we evaluate each method by calculating the spectral TC for carbon nanotubes, graphene, and silicon. We show that each method qualitatively agrees except at optical phonon frequencies, where a combination of mismatched eigenvectors and a large density of states produces artificial TC peaks for modal analysis (MA) methods. Our calculations also show that the HNEMA and SHC methods converge much faster than the GKMA method, with the SHC method being the most computationally efficient. Finally, we demonstrate that our MA implementation in the Graphics Processing Units Molecular Dynamics code on a single graphics processing unit is over 1000 times faster than the existing implementation in the Large-scale Atomic/Molecular Massively Parallel Simulator code on one central processing unit.

Funding

ASCENT, one of the six centers in JUMP, a Semiconductor Research Corporation (SRC) program sponsored by DARPA

Academy of Finland through its QTF Center of Excellence (Project No. 312298)

National Natural Science Foundation of China (NSFC; No. 11974059)

History

School

  • Science

Department

  • Mathematical Sciences

Published in

Physical Review B

Volume

103

Issue

20

Publisher

American Physical Society (APS)

Version

VoR (Version of Record)

Rights holder

© American Physical Society

Publisher statement

This paper was accepted for publication in the journal Physical Review B and the definitive published version is available at https://doi.org/10.1103/physrevb.103.205421

Acceptance date

07/04/2021

Publication date

2021-05-17

Copyright date

2021

ISSN

2469-9950

eISSN

2469-9969

Language

en

Depositor

Prof Tapio Ala-Nissila. Deposit date: 27 October 2021

Article number

205421