Thermal boundary conductance and thermal rectification in molecules.

An approach is presented to calculate thermal boundary resistance in molecules, which occurs, for example, at the interfaces between moieties held at fixed temperatures and a molecular bridge that connects them. If the vibrational frequencies of each moiety lie outside of the band of heat-carrying modes of the bridge, anharmonic interactions mediate thermal conduction at the boundaries. We have expressed thermal boundary conductance in terms of the low-order anharmonic interactions between a moiety and a molecular bridge. Differences in the temperature-dependent boundary conductance at each end of the bridge can be exploited in the design of a molecular thermal diode. The approach is illustrated with the calculation of thermal boundary conductance and thermal rectification in azulene-(CH2)N-anthracene.