Berlin 2024 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.40: Poster

Mittwoch, 20. März 2024, 18:00–20:30, Poster E

Efforts to make Josephson junction on a quantum anomalous Hall insulator — •Bibek Bhujel¹, Anjana Uday¹, Gertjan Lippertz^1,2, Kristof Moors³, Henry F. Legg⁴, Andrea Bliesener¹, Lino M. C. Pereira², Alexey A. Taskin¹, and Yoichi Ando¹ — ¹Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937 Köln, Germany — ²KU Leuven, Quantum Solid State Physics, Celestijnenlaan 200 D, 3001 Leuven, Belgium — ³Peter Grünberg Institute 9, Forschungszentrum Jülich & JARA Jülich-Aachen Research Alliance, 52425 Jülich, Germany — ⁴Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland

Recently, we obtained evidence for superconducting pair correlation in the chiral edge states of a vanadium-doped (Bi_xSb_1−x)₂Te₃ thin film that is tuned to the quantum anomalous Hall insulator phase, by observing the negative nonlocal resistance downstream from a narrow superconducting (grounded) Nb finger electrode [1]. This negative downstream resistance is due to the crossed Andreev reflection (CAR) process, which creates superconducting correlations in the chiral edge. To further investigate the superconducting proximity effect, we are currently fabricating Josephson junction on QAHI. This is a difficult experiment because the 2D "bulk" of the QAHI is insulating and the ferromagnetism works against superconductivity. We will report the progress we have made so far by using Nb electrodes.

[1] A. Uday et al., arXiv:2307.14196

Keywords: Superconducting proximity effect; Quantum anomalous Hall insulator; Chiral edge state; Josephson junction; Superconducting correlation