Bound states 2023

Unidimensional Andreev bound states using quantum Hall edges

Julien Barrier1,2, Na Xin1,2, and A. K. Geim1

1 Department of Physics and Astronomy, University of Manchester, Oxford Road, M13 9PL Manchester, UK
2 National Graphene Institute, Oxford Road, M13 9PL Manchester, UK

A supercurrent flow in a superconductor-normal metal-superconductor junction is made possible via resonances of normal charge carriers (electrons and holes): Andreev bound states, transmitting Cooper pairs in the superconductors. Engineering superconductivity in the quantum Hall regime is a promising route to create novel electronic states [1,2], but, in this regime different carriers move on opposite device sides which necessitates a tedious coupling between distant edges to achieve small supercurrents [3-5].

Here we present a new geometry where quantum Hall edge states are carried along narrow domain walls (DWs) at the centre of the device allowing localised Andreev bound states insensitive to the magnetic field [6]. At magnetic fields as high as 8 T, we observe Josephson coupling with relatively large critical currents. We find superconducting interferences between domain walls and Fabry-Pérot oscillations in individual DWs, effects attributed unambiguously to a 1D nature.

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[6] J. Barrier et al. in preparation.