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Title: Thermal conductivity of graphene mediated by strain and size

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 strainmore » and size.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Jinan Univ., Guanzhou (China); The Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
  2. The Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong); Hong Kong Polytechnic Univ. Shenzhen Research Institute, Shenzhen (China)
  3. Jinan Univ., Guanzhou (China)
  4. The Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
Accepted Manuscript
Journal Name:
International Journal of Heat and Mass Transfer
Additional Journal Information:
Journal Volume: 101; Journal ID: ISSN 0017-9310
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
77 NANOSCIENCE AND NANOTECHNOLOGY; phonon thermal transport; graphene; first principles; strain and size effects
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1328541