Thermal rectification in asymmetric U-shaped graphene flakes

In this paper, we study the thermal rectification in asymmetric U-shaped graphene flakes by using nonequilibrium molecular dynamics simulations. The graphene flakes are composed by a beam and two arms. It is found that the heat flux runs preferentially from the wide arm to the narrow arm which indicates a strong rectification effect. The dependence of the rectification ratio upon the heat flux, the length and the width of the beam, the length and width of the two arms are studied. The result suggests a possible route to manage heat dissipation in U-shaped graphene based nanoelectronic devices.Comment: 3 pages, 4 figure

Heat conduction in graphene flakes with inhomogeneous mass interface

National Natural Science Foundation of China [10775115, 10925525]Using nonequilibrium molecular dynamics simulations, we study the heat conduction in graphene flakes composed by two regions. One region is mass-loaded and the other one is intact. It is found that the mass interface between the two regions greatly decreases the thermal conductivity, but it would not bring about a thermal rectification effect. The dependence of thermal conductivity upon the heat flux and the mass difference ratio is studied to confirm the generality of the result. The interfacial scattering of solitons is studied to explain the absence of the rectification effect

Heat conduction in graphene flakes with inhomogeneous mass interface

Using nonequilibrium molecular dynamics simulations, we study the heat conduction in graphene flakes composed by two regions. One region is mass-loaded and the other one is intact. It is found that the mass interface between the two regions greatly decreases the thermal conductivity, but it would not bring thermal rectification effect. The dependence of thermal conductivity upon the heat flux and the mass difference ratio are studied to confirm the generality of the result. The interfacial scattering of solitons is studied to explain the absence of rectification effect.Comment: 5 pages, 4 figure

Ice or water: thermal properties of monolayer water adsorbed on a substrate

National Natural Science Foundation of China [11290164, 10925525, 11204341]; Shanghai Institute of Applied Physics, Chinese Academy of Sciences; Shanghai Committee of Science and Technology [11DZ1500400]Adsorbed water molecules on an ionic surface may exhibit an ordered monolayer on the surface. The ordered structure gives it many unique properties that are distinct from either liquid water or ice. We use molecular dynamics simulations to investigate the thermal properties of monolayer water, and find that its thermal conductivity is more similar to ice than to liquid water. The dependence of the thermal conductivity on the charge on the substrate and the temperature are studied. This study explores the density distribution of the water molecules to explain the dependence relations, and examines the effect of bulk water on the structure and thermal properties of monolayer water. Furthermore, kinetic energy transportation in monolayer water is studied