LNQE-Kolloquium
Zeit: Mittwoch 14.01.2015 um 17:30 Uhr + anschließendes Get-Together
Ort: im Seminarraum + Foyer des LNQE-Forschungsbaus (Gebäude 3430), Schneiderberg 39, 30167 Hannover, Deutschland
Abstract
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 minor role in the thermoelectric transport in bulk materials [1], it will be shown that they severely contribute to the transport in nanostructures due to their high surface-to-volume ratio [2-4]. Specifically, thermoelectric and magnetotransport experiments on ALD-grown Sb2Te3 thin films as well as on VLS-grown Sb2Te3 and Bi2Te3 nanowires are presented and the results of which are interpreted using thermoelectric transport calculations [5]. In all systems investigated, the maximum TE performance converges towards the maximum TE performance of the surface states with decreasing system size into the nanometer-range, limiting their application in efficient thermoelectric devices.
References:
[1] Kornelius Nielsch, Julien Bachmann, Johannes Kimling, and Harald Böttner, "Thermoelectric Nanostructures: From Physical Model Systems towards Nanograined Composites", Adv. Eng. Mater. 1, 713-731 (2011).
[2] Bacel Hamdou, Johannes Gooth, August Dorn, Eckhard Pippel, and Kornelius Nielsch, "Aharonov-Bohm oscillations and weak antilocalization in topological insulator Sb2Te3 nanowires", Appl. Phys. Lett. 102, 22110 (2013).
[3] Bacel Hamdou, Johannes Gooth, August Dorn, Eckhard Pippel, and Kornelius Nielsch, "Surface state dominated transport in topological insulator Bi2Te3 nanowires", Appl. Phys. Lett. 103, 193107 (2013).
[4] Johannes Gooth, Bacel Hamdou, August Dorn, Robert Zierold, and Kornelius Nielsch, "Resolving the Dirac cone on the surface of Bi2Te3 topological insulator nanowires by field-effect measurements" Appl. Phys. Lett. 104, 243115 (2014).
[5] Johannes Gooth, Jan Goeran Gluschke, Robert Zierold, Martin Leijnse, Heiner Linke, Kornelius Nielsch, “Thermoelectric performance of classical topological insulator nanowires”, arXiv:1405.1592 (2014).
