Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 57: Topology: Poster
TT 57.8: Poster
Wednesday, March 20, 2024, 15:00–18:00, Poster E
Exploring the Effects of a 1D Periodic Potential on a 3D Topological Insulator — •Albert Koop, Alexander Altmann, Dimitriy Kozlov, and Dieter Weiss — Institute of Experimental and Applied Physics, University of Regensburg, Germany
In this work, we have investigated the effect of a weak 1-dimensional periodic potential on the conductivity of 3D high-mobility topological insulator (TI) based on 80nm HgTe film. A stripe gate formed the modulation potential, while a uniform gate additionally covered the whole structure. This makes it possible to change both the position of the Fermi level and the strength of the 1D potential. The classical magnetoresistance ρxx manifests a pronounced oscillation with minima described by the commensurability condition 2Rc/a= (λ−1/4) with λ = 1,2,3... where Rc is the cyclotron radius and a is the period of the 1D potential. We observed the commensurability features coming from both electrons and holes. On the electron side, the contribution of top-surface electrons (i.e., topological electrons located closer to the gate) dominated in the observed pattern, while all other carriers acted as a background. However, in the valence band, where bulk holes and Dirac electrons coexist, we observed the previously unexplored situation that both electrons and holes can contribute to the commensurability oscillations.
HgTe provided by N. Mikhailov and S. A. Dvoretskii, Novosibirsk.
Keywords: Weiss oscillations; 3D topological insulator; 1-dimensional periodic potential; commensurability oscillations; Drude conductivities