The molecular dynamics simulation of monocrystal carbon, silicon and germanium thermal conductivity

In this paper the thermal conductivities of monocrystal carbon, silicon, and germanium nanometer thin film are simulated respectively using non-equilibrium molecular dynamics (NEMD) method and corresponding Tersoff potential energy function. The simulation results indicate that the thermal conductivities of those nanometer thin films are obviously lower than the corresponding thermal conductivities of their bulk crystals under the same temperature. The thermal conductivities increase with the increasing of thin film thickness, and the conductivities have an approximately linear relationship with thickness of the thin films. The curve slope of carbon thermal conductivity is larger than that of silicon and germanium. The calculation results of thermal conductivities demonstrate distinct size effect. In normal direction, the thin film thermal conductivities of carbon, silicon and germanium crystals decline with the increasing of temperature, and the declining degree steps down in the sequence of carbon, silicon and germanium.