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Andreev reflection at high magnetic fields: Evidence for electron and hole transport in edge states

J. Eroms·D. Weiss·J. De Boeck·G. Borghs·U. Zülicke
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Abstract

We have studied magnetotransport in arrays of niobium filled grooves in an InAs/AlGaSb heterostructure. The critical field of up to 2.6 T permits to enter the quantum Hall regime. In the superconducting state, we observe strong magnetoresistance oscillations, whose amplitude exceeds the Shubnikov-de Haas oscillations by a factor of about two, when normalized to the background. Additionally, we find that above a geometry-dependent magnetic field value the sample in the superconducting state has a higher longitudinal resistance than in the normal state. Both observations can be explained with edge channels populated with electrons and Andreev reflected holes.

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J. Eroms, D. Weiss, J. De Boeck, G. Borghs, U. Zülicke. 2005-07-20. Andreev reflection at high magnetic fields: Evidence for electron and hole transport in edge states. https://doi.org/10.1103/physrevlett.95.107001

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