SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 8: Focus Session: Emerging Phenomena in Superconducting Low Dimensional Hybrid Systems II

TT 8.5: Talk

Tuesday, September 28, 2021, 14:45–15:00, H7

Supercurrent-enabled Andreev reflection in a chiral quantum Hall edge state — •Andreas Bock Michelsen^1,2, Patrik Recher³, Bernd Braunecker¹, and Thomas Schmidt² — ¹SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK — ²Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg, Luxembourg — ³Institut für Mathematische Physik, Technische Universität Braunschweig, 38106 Braunschweig, Germany

A chiral, spinless quantum Hall edge state placed in proximity to an s-wave superconductor experiences induced superconducting correlations. This effect provides a promising pathway to the realization of Majorana zero-modes and their parafermionic generalizations as non-Abelian anyons. Recent experiments have observed the phenomenon through conductance signatures of the mediating process of Andreev reflection, where electrons tunnel in pairs. We develop a tunneling model of the system and demonstrate that this process is enabled by the superconductor surface hosting spin-orbit coupling and a supercurrent induced by the strong magnetic field. By integrating out the superconductor we develop an effective model of the proximitized edge state, and derive an expression for the probability of an electron being transported as a hole through the edge state. This lets us analytically predict the outcome of conductance measurements given external experimental parameters.