Scientific Events

Speaker: Dr. Gabi Schierning Location: Max-Planck-Institut für Eisenforschung GmbH

Making quantum transport visible in thermoelectric Bi2Te3 nanoparticles

Bi2Te3, Sb2Te3, and Bi2Se3, well established thermoelectric materials, are also three-dimensional (3D) topological insulators (TI) exhibiting a bulk bandgap and highly conductive, robust, gapless surface states. While the transport properties of 3D TIs are of utmost importance for potential applications, they are difficult to characterize. The reason is that transport in those materials is always dominated by bulk carriers. Still, the signature of the nontrivial electronic band structure on the thermoelectric transport properties can be evidenced in transport experiments using nanostructures with a high surface-to-volume ratio. Using a nanoparticle-based materials’ design, the highly porous macroscopic sample features a carrier density of the surface states in a comparable order of magnitude as the bulk carrier density. Further, the sintered nanoparticles impose energetic barriers for the transport of bulk carriers (hopping transport), while the connected surfaces of the nanoparticles provide a 3D percolation path for surface carriers. Within this work, I will discuss the nanoparticle processing as well as the transport properties of these combined thermoelectric and 3D TI samples. [more]
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