Journal
PHYSICS LETTERS A
Volume 380, Issue 24, Pages 2105-2110Publisher
ELSEVIER
DOI: 10.1016/j.physleta.2016.04.024
Keywords
Non-Fourier heat conduction; Graphene; Mechanical wave; Molecular dynamics simulation
Categories
Funding
- National Natural Science Foundation of China [51322603, 51136001, 51356001]
- Science Fund for Creative Research Groups [51321002]
- Program for New Century Excellent Talents in University
- Tsinghua University Initiative Scientific Research Program
- Tsinghua National Laboratory for Information Science and Technology of China
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Using non-equilibrium molecular dynamics simulations, we systematically investigate the non-Fourier heat conduction in graphene under steady high heat flux. The results show that if two triggering factors, i.e. steady high heat flux and tensile stress, are satisfied simultaneously, a low-frequency mechanical wave and corresponding wave-like energy profile can be observed, which are distinctly different from ripples and linear temperature profile of the normal Fourier heat conduction. This mechanical wave provides an additional channel of heat transport and renders graphene more conductive without changing its pristine thermal conductivity. What's more, as the heat flux or original bond length increases, its frequency increases and energy transported by this mechanical wave is also on the rise. Further analyses show that such anomalous phenomenon is not arising from the high-energy or high-frequency pulses and also not artifacts of the velocity-exchange method. It is a dissipative structure, a new order state far from thermodynamic equilibrium, and the corresponding nonlinear relationship between the gradient of the wave-like kinetic temperature and the heat flux enables more efficient heat transport in graphene. (C) 2016 Elsevier B.V. All rights reserved.
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