- Kornelius Nielsch, Leibnitz Institute of Solid State and Materials, Dresden, Germany
In this presentation we challenge the interconnection between thermoelectric performance and the topological insulator nature of chalcogenide-type materials. While topological surface states seem to play a minor role in the thermoelectric transport in nanograined bulk materials, it will be shown that they severely contribute to the transport in nanostructures due to their high surface-to-volume ratio. For thermoelectric conversion processes near room temperature and up to 200°C, Bi2Te3 and related materials are the dominating materials for devices, and many attempts to replace this material class have failed. For decades it was known that heavy elements efficiently damp phonons. In the past 5 years we have learned that Bi2Te3 and Bi2Se3, due to strongly spin-orbit coupling, exhibit topical surface states and are 3D topological insulators. That finding has stimulated the research on novel materials such as SnSe, which exhibit topological surface states.
About the Speaker:
Dr. Kornelius Nielsch is the director of the institute of Metallic Materials at IFW Dresden and a full professor at TU Dresden.