Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 42: 2D Materials 6 (joint session HL/CPP/DS)
HL 42.1: Vortrag
Freitag, 9. September 2022, 09:30–09:45, H36
THz conductivity of nanograined Bi2Te3 pellets with varying Te doping — •Ahana Bhattacharya1, JeongWoo Han1, Sepideh Izadi2, Sarah Salloum3, Stephan Schulz3, Gabi Schierning2, and Martin Mittendorff1 — 1Universität Duisburg-Essen, Fakultät für Physik, 47057 Duisburg, Germany — 2Universität Bielefeld, Fakultät für Physik, 33615 Bielefeld, Germany — 3Universität Duisburg-Essen, Fakultät für Chemie, 45141 Essen, Germany
The topological insulator Bi2Te3 hosts surface states with a high carrier mobility as back scattering of charge carriers is suppressed due to the spin-momentum locking. While in large crystals the electronic properties are dominated by the bulk states, hot-pressed pellets of nanograined Bi2Te3 offer a high surface-to-volume ratio, which provides a platform to exploit the surface carriers even in extended samples. Here we employ THz time-domain spectroscopy to disentangle the contribution of surface and bulk carriers to the transport properties. Even at room temperature the THz reflection is determined by characteristic features of the high-mobility surface carriers, i.e. Drude conductivity but also plasmonic contributions. The latter are caused by confinement of the surface carriers due to the mechanical structure of the sample. Variations of the Te content allows to shift the Fermi energy and thus strongly influences the resulting THz spectra.