Thermal conductivity of graphene mediated by strain and size

Youdi Kuang, Lucas Lindsay, San-Qiang Shi, Xinjiang Wang, Baoling Huang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

40 Citations (Scopus)

Abstract

Based on first-principles calculations and full iterative solution of the linearized Boltzmann-Peierls transport equation for phonons, we systematically investigate effects of strain, size and temperature on the thermal conductivity k of suspended graphene. The calculated size-dependent and temperature-dependent k for finite samples agree well with experimental data. The results show that, contrast to the convergent room-temperature k = 5450 W/m-K of unstrained graphene at a sample size ∼8 cm, k of strained graphene diverges with increasing the sample size even at high temperature. Out-of-plane acoustic phonons are responsible for the significant size effect in unstrained and strained graphene due to their ultralong mean free path and acoustic phonons with wavelength smaller than 10 nm contribute 80% to the intrinsic room temperature k of unstrained graphene. Tensile strain hardens the flexural modes and increases their lifetimes, causing interesting dependence of k on sample size and strain due to the competition between boundary scattering and intrinsic phonon-phonon scattering. k of graphene can be tuned within a large range by strain for the size larger than 500 μm. These findings shed light on the nature of thermal transport in two-dimensional materials and may guide predicting and engineering k of graphene by varying strain and size.
Original languageEnglish
Pages (from-to)772-778
Number of pages7
JournalInternational Journal of Heat and Mass Transfer
Volume101
DOIs
Publication statusPublished - 1 Oct 2016

Keywords

  • First principles
  • Graphene
  • Phonon thermal transport
  • Strain and size effects

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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