Ballistic thermal resistance of graphene nano-junctions is investigated using non-equifibrium molecular dynamics simulation. The simulation system is consisted of two symmetrical trapezoidal or rectangular graphene na...Ballistic thermal resistance of graphene nano-junctions is investigated using non-equifibrium molecular dynamics simulation. The simulation system is consisted of two symmetrical trapezoidal or rectangular graphene nano- ribbons （GNRs） and a connecting nanoscale constriction in between. Prom the simulated temperature profile, a big temperature jump resulted from the constriction is found, which is proportionM to the heat current and corresponds to a local ballistic thermal resistance. Fixing the constriction width and the length of GNRs, this ballistic thermal resistance is independent of the width of the GNRs bottom layer, i.e., the convex angle. But interestingly, this thermal resistance has obvious size effect. It is inversely proportional to the constriction width and will disappear with the constriction being wider. Moreover, based on the phonon dynamics theory, a theoretical model of the ballistic thermal resistance in two-dimensional nano-systems is developed, which gives a good explanation on microcosmic level and agrees well with the simulation result quantitatively and qualitatively.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.51322603,51136001,51356001Science Fund for Creative Research Groups(No.51321002)+1 种基金the Program for New Century Excellent Talents in University,Tsinghua University Initiative Scientific Research Programthe Tsinghua National Laboratory for Information Science and Technology of China
文摘Ballistic thermal resistance of graphene nano-junctions is investigated using non-equifibrium molecular dynamics simulation. The simulation system is consisted of two symmetrical trapezoidal or rectangular graphene nano- ribbons （GNRs） and a connecting nanoscale constriction in between. Prom the simulated temperature profile, a big temperature jump resulted from the constriction is found, which is proportionM to the heat current and corresponds to a local ballistic thermal resistance. Fixing the constriction width and the length of GNRs, this ballistic thermal resistance is independent of the width of the GNRs bottom layer, i.e., the convex angle. But interestingly, this thermal resistance has obvious size effect. It is inversely proportional to the constriction width and will disappear with the constriction being wider. Moreover, based on the phonon dynamics theory, a theoretical model of the ballistic thermal resistance in two-dimensional nano-systems is developed, which gives a good explanation on microcosmic level and agrees well with the simulation result quantitatively and qualitatively.
