Thermal conductivity reduction mechanisms in superlattices

The large thermal conductivity reduction observed in superlattices has led to the reports of significantly increased thermoelectric figure-of-merit by several groups. The mechanisms of thermal conductivity reduction in superlattices were scrutinized from different angles over the last decade. This paper summarizes our current understanding on the heat conduction mechanisms in superlattices. Among several potential mechanisms, the interface scattering, particularly diffuse interface scattering, plays the most important role. Conclusions drawn from the studies on superlattices have implications to other nanostructured thermoelectric materials.