Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 4: Topological Insulators
TT 4.2: Talk
Monday, March 17, 2025, 09:45–10:00, H33
Thermopower and resistivity of the topological insulator Bi2Te3 in the amorphous and crystalline phase — •Ena Osmic1,2, Jose Barzola Quiquia3, Stephan Winnerl4, Winfried Böhlmann5, Peter Häussler3, and Joachim Wosnitza1,2 — 1Hochfeld-Magnetlabor Dresden (HLD-EMFL), HZDR, Dresden, Germany — 2Institut für Festkörper- und Materialphysik, TU Dresden, Germany — 3Division of Thin Film Physics, TU Chemnitz, Germany — 4Institut für Ionenstrahlphysik und Materialforschung, HZDR, Dresden, Germany — 5Felix-Bloch Institute for Solid-state Physics, Universität Leipzig, Germany
We investigated the temperature dependence of the thermopower S(T) and resistance R(T) in thin films of the topological insulator Bi2Te3, prepared in situ by sequential flash-evaporation at 4 K. In the amorphous phase, S(T) is negative and significantly larger than in other amorphous materials, while in the crystalline phase, it remains negative and shows a linear temperature dependence. The resistivity ρ(T) transitions from semiconducting behavior in the amorphous state to linear metallic behavior upon crystallization. For T > 15 K , the linear ρ(T) reflects metallic surface states typical of topological insulators, while for T < 10 K , the conductivity shows a logarithmic temperature dependence dominated by electron-electron interactions. Raman spectroscopy confirms crystallization in the trigonal R3m space group, and energy-dispersive X-ray spectroscopy indicates high compositional homogeneity with no magnetic impurities.
Keywords: Electron-Electron Interaction; Resistance; Thermopower; Raman spectroscopy