4?-periodic Josephson supercurrent in HgTe-based topological Josephson junctions

4?-periodic Josephson supercurrent in HgTe-based topological Josephson junctions

Wiedenmann, J.
Bocquillon, E.
Deacon, R.S.
Hartinger, S.
Hermann, O.
Klapwijk, T.M.
Maier, L.
Ames, C.
Brüne, C.
Gould, C.
Oiwa, A.
Ishibashi, K.
Tarucha, S.
Buhmann, H.
Molenkamp, L.W.

Applied Sciences

QN/Quantum Nanoscience

2016-01-21

The Josephson effect describes the generic appearance of a supercurrent in a weak link between two superconductors. Its exact physical nature deeply influences the properties of the supercurrent. In recent years, considerable efforts have focused on the coupling of superconductors to the surface states of a three-dimensional topological insulator. In such a material, an unconventional induced p-wave superconductivity should occur, with a doublet of topologically protected gapless Andreev bound states, whose energies vary 4?-periodically with the superconducting phase difference across the junction. In this article, we report the observation of an anomalous response to rf irradiation in a Josephson junction made of a HgTe weak link. The response is understood as due to a 4?-periodic contribution to the supercurrent, and its amplitude is compatible with the expected contribution of a gapless Andreev doublet. Our work opens the way to more elaborate experiments to investigate the induced superconductivity in a three-dimensional insulator.

physical sciences
condensed matter

http://resolver.tudelft.nl/uuid:3177aab7-3fdf-4467-8ea8-afcad591b92b

Nature Publishing Group

2041-1723

https://doi.org/10.1038/ncomms10303

Nature Communications, 7, 2016

Institutional Repository

journal article

(c) 2016 The Author(s)
CC BY - This work is licensed under a Creative Commons Attribution 4.0 International License.