Berlin 2024 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 74: Topological Insulators

TT 74.3: Talk

Thursday, March 21, 2024, 15:30–15:45, H 3005

Nonreciprocal charge transport in nanowires of MBE-grown topological insulator /superconductor heterostructure — •Roozbeh Yazdanpanah, Jens Brede, Alexey Taskin, and Yoichi Ando — University of Cologne, Cologne, Germany

In systems with broken inversion and time reversal symmetry, magnetochiral anisotropy (MCA) leads to such nonreciprocal transport which depends both on the current amplitude and the applied magnetic field. The MCA effect in gated nanowires of a topological insulator (TI) leads to considerable current nonreciprocity[1]. Additionally, the MCA in a superconductor (SC) in the fluctuation regime also results in nonreciprocal effects, which is also the case for stacks of TI/SC[2]. We studied the combination of these two effects. For this purpose, thin films of (Bi_1−xSb_x)₂Te₃ on PdTe₂ were grown in an MBE chamber and nanowires of different widths were fabricated. Second harmonics measurements were performed to study the nonreciprocal charge transport in these nanowires. A clear enhancement of the MCA was observed in a nanowire with 100-nm width even without gating.

[1] H.F. Legg et al., Nat. Nanotechnol. 17 (2022) 696.

[2] M. Masuko et al., npj Quantum Materials 7 (2022) 104.

Keywords: Noreciprocal transport; Topological insulator; Superconductivity