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arXiv · 1411.7794

Conductance oscillations at the interface between a superconductor and the helical edge channel in a narrow HgTe quantum well

A. Kononov·S. V. Egorov·N. Titova·Z. D. Kvon·N. N. Mikhailov·S. A. Dvoretsky·E. V. Deviatov
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Abstract

We experimentally investigate electron transport through the interface between a superconductor and the edge of a two-dimensional electron system with band inversion. The interface is realized as a tunnel NbN side contact to a narrow 8~nm HgTe quantum well. It demonstrates a typical Andreev behavior with finite conductance within the superconducting gap. Surprisingly, the conductance is modulated by a number of equally-spaced oscillations. The oscillations are present only within the superconducting gap and at lowest, below 1~K, temperatures. The oscillations disappear completely in magnetic fields, normal to the two-dimensional electron system plane. In contrast, the oscillations' period is only weakly affected by the highest, up to 14~T, in-plane oriented magnetic fields. We interpret this behavior as the interference oscillations in a helical one-dimensional edge channel due to a proximity with a superconductor.

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A. Kononov, S. V. Egorov, N. Titova, Z. D. Kvon, N. N. Mikhailov, S. A. Dvoretsky, E. V. Deviatov. 2014-11-28. Conductance oscillations at the interface between a superconductor and the helical edge channel in a narrow HgTe quantum well. https://doi.org/10.1134/s0021364015010075

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