Thermal rectification mechanisms including noncontinuum effects

Thermal rectification is a physical phenomenon where the resistance to heat flow is dependent on the sign of the temperature difference across a solid. This effect could be a useful phenomena to many industries if it could be controlled and optimized. However, experimental evidence shows that thermal rectification is dependent on a large number of competing factors. In addition, theoretical models that allow thermal rectification do not match measurements well largely because of the complexity of the effect and the immaturity of the models. Nevertheless, several mechanisms (geometric, electronic, electron-phonon scattering and anharmonic lattice vibrations) have been identified as possible means to control interface conductance at interfaces. Currently no evidence exists that suggests that the difference in conductance can reach one order of magnitude, which is an arbitrary limit required to deem the effect useful for engineered systems.