Interface effects in thermal conduction through molecular junctions: Numerical simulations

Thermal conductance in solid-molecule-solid junctions is studied within Langevin-type classical molecular dynamics simulations. The solids attached at the two ends, characterized by phonon bands mismatching the molecular vibrational window, are simulated using colored thermal noises with analytic correlation functions. We find that the dissimilarity in the vibrational spectra of the molecule and the interfacing materials crucially controls both the magnitude and the chain-length dependence of the heat current considering both harmonic and anharmonic molecules. By using reservoirs with distinct spectral functions, we also demonstrate that one can optimize the thermal rectifying (diodelike) properties of the junction.