Necessary conditions for thermal rectification and negative differential thermal conductance in graphene nanoribbons

2011 ◽  
Vol 1347 ◽  
Author(s):  
Yan Wang ◽  
Xiulin Ruan
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Necessary Conditions ◽  
Graphene Nanoribbons ◽  
Ballistic Transport ◽  
Thermal Conductance ◽  
Nonequilibrium Molecular Dynamics ◽  
Thermal Rectification ◽  
Preferred Direction ◽  
Dynamics Simulations

ABSTRACTWe have studied negative differential thermal conductance (NDTC) and thermal rectification (TR) in graphene nanoribbons (GNRs) using nonequilibrium molecular dynamics simulations. Strong ballistic transport regime and sufficient temperature gradient are found to be necessary conditions for the onset of both NDTC and TR in GNRs, while the latter also requires asymmetry in structure. Preferred direction of heat transport is also discussed for TR.

Linear and Nonlinear Thermal Transport in Graphene: Molecular Dynamics Simulations

2011 ◽  
Vol 1347 ◽  
Author(s):  
Bo Qiu ◽  
Yan Wang ◽  
Xiulin Ruan
Keyword(s):  
Molecular Dynamics ◽  
Thermal Transport ◽  
Graphene Nanoribbons ◽  
Ballistic Transport ◽  
Thermal Conductance ◽  
Md Simulations ◽  
Spectral Energy ◽  
Suspended Graphene ◽  
Thermal Rectification ◽  
Dynamics Simulations

AbstractIn this work, we perform molecular dynamics (MD) simulations to study the linear thermal transport in suspended graphene and the nonlinear thermal transport phenomena in graphene nanoribbons (GNR). We use spectral energy density analysis to quantitatively address the relative importance of different types of phonon in thermal transport in suspended graphene. Negative differential thermal conductance (NDTC) and thermal rectification in graphene nanoribbons have been studied using nonequilibrium molecular dyanmics simulations. Ballistic transport regime, sufficient temperature nonlinearity and asymmetry are found to be necessary conditions for the onset of these behaviors.

Heat controlling in the mass-graded harmonic lattices with double-well on-site potential

2018 ◽  
Vol 32 (20) ◽  
pp. 1850217
Author(s):  
Peng Kong ◽  
Zhengzheng Wei ◽  
Tao Hu ◽  
Yi Tang
Keyword(s):  
Molecular Dynamics ◽  
Heat Flux ◽  
Power Spectrum ◽  
Molecular Dynamics Simulations ◽  
Heat Transport ◽  
Nonequilibrium Molecular Dynamics ◽  
Thermal Rectification ◽  
Average Temperature ◽  
New Type ◽  
Dynamics Simulations

Using nonequilibrium molecular dynamics simulations, we investigate thermal rectification in mass-graded lattices with a new type on-site potential which has a physical picture of the double-well. By adjusting the ratio of harmonic on-site potential and anharmonic on-site potential, we could obtain the optimal heat transport and the best thermal rectification. In addition, we observe the reversal thermal rectification by changing the ratio of on-site potential and analyzes the mechanism of thermal rectification through the power spectrum. At last, we also study the heat flux and thermal rectification in a different case of average temperature and mass gradient.

Thermal Conductivity of Graphene on Nanostructure Size from Nonequilibrium Molecular Dynamics Simulations

2020 ◽  
Vol 17 (4) ◽  
pp. 1566-1570
Author(s):  
Xianqi Wei ◽  
Zelin Li ◽  
Junchen Lu ◽  
Shunlong Xu ◽  
Yuancheng Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Thermal Management ◽  
Strong Dependence ◽  
Thermal Conductance ◽  
Mean Free Path ◽  
Dynamics Simulation ◽  
Nonequilibrium Molecular Dynamics ◽  
Edge Type ◽  
Dynamics Simulations

Thermal transport of graphene occupies a unique place in thermal management of electronic devices, especially for nanosize devices with high-density integration and high dissipated power. The structure of graphene on nanometer scale changes its thermal conductance. Here, the thermal characters of graphene have been researched by nonequilibrium molecular dynamics simulation (NEMDS) at room temperature. Special attention is focused on the edge type (zigzag or armchair) and nanostructure size dependence of conductivity for heat. The consequences suggest that the thermal conductivity of zigzag edge has been higher than that of armchair, which is because of the higher phonon group velocities. Furthermore, thermal conductivity shows a rising tendency, when the model is calculated from length of 21.84 nm to 43.78 nm. The result indicates that the thermal property performs a strong dependence on nanostructure size which is less than phonon mean free path (775 nm). Our research highlights the significance of structure attribute relationships together with providing useful guideline in calculations for nanosize devices thermal management.

scholarly journals The effects of Stone–Wales defects on the thermal properties of bilayer armchair graphene nanoribbons

RSC Advances ◽  
2020 ◽  
Vol 10 (33) ◽  
pp. 19254-19257
Author(s):  
Xingli Zhang ◽  
Jinglan Zhang ◽  
Ming Yang
Keyword(s):  
Molecular Dynamics ◽  
Thermal Properties ◽  
Molecular Dynamics Simulations ◽  
Graphene Nanoribbons ◽  
Bilayer Graphene ◽  
Nonequilibrium Molecular Dynamics ◽  
Armchair Graphene Nanoribbons ◽  
Dynamics Simulations ◽  
Armchair Graphene

We investigate the influence of Stone–Wales (S–W) defects on the thermal properties of bilayer graphene nanoribbons (BGNRs) with armchair edges by nonequilibrium molecular dynamics simulations (NEMD).

Thermal Rectification of Silicene Nanosheets With Triangular Cavities by Molecular Dynamics Simulations

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Yuan Feng ◽  
Xingang Liang
Keyword(s):  
Molecular Dynamics ◽  
Thermal Transport ◽  
Simulation Method ◽  
Nonequilibrium Molecular Dynamics ◽  
Dimensional Structure ◽  
Honeycomb Lattice ◽  
Rectification Effect ◽  
Thermal Rectification ◽  
Dynamics Simulations ◽  
Silicon Based

Silicene, the silicon-based two-dimensional structure with honeycomb lattice, has been discovered and expected to have tremendous application potential in fundamental industries. However, its thermal transport mechanism and thermal properties of silicene have not been fully explained. We report a possible way to control the thermal transport and thermal rectification in silicene nanosheets by distributing triangular cavities, which are arranged in a staggered way. The nonequilibrium molecular dynamics (NEMD) simulation method is used. The influences of the size, number, and distribution of cavities are investigated. The simulation results show that reflections of phonon at the vertex and the base of the triangular cavities are quite different. The heat flux is higher when heat flow is from the vertex to the base of cavities, resulting in thermal rectification effect. The thermal rectification effect is strengthened with increasing cavity size and number. A maximum of thermal rectification with varying distance between columns of cavities is observed.

Thermal Rectification Characteristics of Graphene Nanoribbons of Asymmetric Geometries

MRS Advances ◽  
2016 ◽  
Vol 2 (1) ◽  
pp. 15-20
Author(s):  
T. Iwata ◽  
K. Shintani
Keyword(s):  
Molecular Dynamics ◽  
Heat Transport ◽  
Density Of States ◽  
Graphene Nanoribbons ◽  
Longitudinal Direction ◽  
Nonequilibrium Molecular Dynamics ◽  
Phonon Density ◽  
Rectification Ratio ◽  
Phonon Density Of States ◽  
Thermal Rectification

ABSTRACTThe rectification of heat in graphene nanoribbons (GNRs) of asymmetric geometries is investigated by means of nonequilibrium molecular dynamics (NEMD). Two kinds of geometries of GNRs are addressed; a trapezoidal or T-shaped step is inserted halfway through a GNR in its longitudinal direction. The thermal conductivities (TCs) of the GNRs in the two longitudinal directions, forward and backward, are calculated making their width and temperature change. It is revealed that the thermal rectification ratio (TRR) of T-shaped GNRs are larger than those of trapezoidal GNRs and that the characteristics of heat transport in such asymmetric GNRs can be understood by considering the local phonon density of states (DOSs).

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