In this presentation, we challenge the interconnection between thermoelectric performance and topological insulator nature of chalcogenide-type materials. While topological surface states seem to play positive role in the thermoelectric transport in (nanograined) bulk material, it will be shown that they severely contribute to the transport in nanostructures due to their high surface-to-volume ratio. By tuning the charge carrier concentration a crossover between a surface-state-dominant and a Fuchs-Sondheimer transport regime is observed in ALD grown Sb2Te3 layers. Magnetic ordering on the surface of a topological insulator nanowire could enable room-temperature topological quantum and spintronic devices. Furthermore, the magneto-thermoelectric transport of ferromagnetic alloys and Weyl semimetal like HfTe5 and NbP will be presented. Many of these so-called quantum materials have been analyzed for thermoelectric applications in previous decades.
Micro-thermoelectric modules are of potential use in fields such as energy harvesting, thermal management, thermal imaging and high spatial-resolution temperature sensing. In particular, micro-thermoelectric coolers (μ-TECs) – in which the application of an electric current cools the device based on the Peltier effect – can be used to manage heat locally on a micrometer spot in microelectronic circuits, optoelectronic devices and microfluidic channels. Here we report the fabrication of μ-TECs based on quantum materials that offer a rapid response time of 1 ms, reliability of up to 10 million cycles and a cooling stability of more than one month at constant electric current. The high cooling reliability and stability for our μ-TEC module  can be attributed to a design of free-standing top contacts between the thermoelectric legs and metallic bridges.
Ref:  G. Li et al Nature Electronics 1, 555 (2018).