Thermal conductivity decomposition in two-dimensional materials: Application to graphene

Zheyong Fan, Luiz Felipe C Pereira, Petri Hirvonen, Mikko M. Ervasti, Ken R. Elder, Davide Donadio, Tapio Ala-Nissilä, Ari Harju

Research output: Contribution to journalArticleScientificpeer-review

85 Citations (Scopus)
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Abstract

Two-dimensional materials have unusual phonon spectra due to the presence of flexural (out-of-plane) modes. Although molecular dynamics simulations have been extensively used to study heat transport in such materials, conventional formalisms treat the phonon dynamics isotropically. Here, we decompose the microscopic heat current in atomistic simulations into in-plane and out-of-plane components, corresponding to in-plane and out-of-plane phonon dynamics, respectively. This decomposition allows for direct computation of the corresponding thermal conductivity components in two-dimensional materials. We apply this decomposition to study heat transport in suspended graphene, using both equilibrium and nonequilibrium molecular dynamics simulations. We show that the flexural component is responsible for about two-thirds of the total thermal conductivity in unstrained graphene, and the acoustic flexural component is responsible for the logarithmic divergence of the conductivity when a sufficiently large tensile strain is applied.

Original languageEnglish
Article number144309
Pages (from-to)1-10
JournalPhysical Review B
Volume95
Issue number14
DOIs
Publication statusPublished - 19 Apr 2017
MoE publication typeA1 Journal article-refereed

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