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TT: Fachverband Tiefe Temperaturen

TT 8: Topological Insulators I (joint session HL/TT)

TT 8.5: Talk

Monday, March 12, 2018, 10:30–10:45, A 151

Multi probe transport measurements on Bi₂Te₃ thin films — •Sebastian Bauer, Stephanie Hoepken, Mandana Soleimani, Christian A. Bobisch, and Rolf Möller — Faculty of Physics, Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47048 Duisburg, Germany

We present a detailed study of the electron transport properties of a thin Bi₂Te₃ film on Si(111). Bi₂Te₃ is a prototype system of so called three dimensional topological insulators. Such materials are insulating inside their bulk while they provide a metallic state on their surface which is protected by the materials topology [1]. The nanoscale transport field of the Bi₂Te₃ surface was studied by scanning tunneling potentiometry (STP), an extension of the scanning tunneling microscope (STM) which allows us to analyze the microscopic topography and the correlated microscopic electrochemical potential of the surface simultaneously [2]. The STP analysis shows that morphological features like step edges and grain boundaries are barriers for conduction electrons. The conductivity of step edges and grain boundaries were determined to 700 S/cm and 350 S/cm in the surface state, confirming former STP studies [3,4].

[1] M. Z. Hasan, C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010). [2] A. Bannani, C. A. Bobisch, R. Möller, Rev. Sci. Instrum. 79, 083704 (2008). [3] S. Bauer und C. A. Bobisch, Nat. Com. 7, 11381 (2016). [4] F. Lüpke et al., Nat. Com. 8, 15704 (2017).