Dynamic response of graphene to thermal impulse

Abstract

A transient molecular dynamics technique is developed to characterize the thermophysical properties of two-dimensional graphene nanoribbons (GNRs). By directly tracking the thermal relaxation history of GNR that is heated by a thermal impulse, we are able to determine its thermal diffusivity fast and accurate. We study the dynamic thermal conductivity of different length GNRs of 1.99 nm width. Quantum correction is applied in all the temperature calculations and is found to have a critical role in thermal transport study for graphene. The calculated specific heat of GNR agrees well with that of graphite at 300.6 and 692.3 K, showing little effect of the unique graphene structure on its ability to store thermal energy. Strong size effect on GNR's thermal conductivity is observed and its theoretical values for infinite length limit are evaluated by data fitting and extrapolation. With infinite length, the

Phonon hydrodynamics and its applications in nanoscale heat transport

“…By contrast, the temporal microscale temperature response behaviors obtained in experiments [305,316] and MD simulation [308,309] fitted reasonably well to the DPL model by adjusting the two phase lags τ q and τ T . In spite of this success, the DPL model gives rise to a parabolic temperature differential equation [37], with no supportive evidence of heat waves in temporal microscale.…”

“…[309]). Experimental attempt [311,312] to seek such heat waves and verify the C-V equation in inhomogeneous medium fails as well, and subsequently, more accurate experiments [313][314][315] show that the Fourier"s law could actually explain the results.…”

“…Combination of C-V equation with energy balance equation results in a hyperbolic temperature differential equation, which in turn predicts a propagation of damping temperature wave. However, numerical simulations by MD [307][308][309] and LBM [310] demonstrate that the C-V equation is unable to describe the short-pulsed laser heating process both in bulk materials and nanostructures (carbon nanotube in Ref.…”

Generalized Two-Temperature Model for Coupled Phonons in Nanosized Graphene

“…Based on the temperature profiles of different phonon groups, we calculated the ph-ph coupling factor Gio, comparable with strength of electron-phonon coupling 19 and found that Gio is not sensitive to system size. We successfully demonstrated the poor coupling between IP and OP phonon groups in graphene [25][26][27][28] . Page 5 In this letter, TTM is used to investigate the ph-ph coupling between OP and IP phonon groups.…”

Thermal transport in nanostructures

“…There are rich physical phenomena about thermal property of GNRs. The effects of size, [95][96][97][98] defects, 99, 100 doping, 101,102 shape, 103,104 stress/strain,, [105][106][107][108] substrates, 109 inter-layer interactions, [110][111][112] nanoscale junctions, 113 chirality, 114 topological structure, 115 edge effect, [116][117][118][119] foldings (gradfolds), 23,120 etc. on thermal conductivity of nanoribbons [121][122][123][124][125][126][127][128] have been widely studied.…”