title: 4π-periodic Josephson supercurrent in HgTe-based topological Josephson junctions.
abstract: 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 4π-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 4π-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.
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Wiedenmann
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Bocquillon
authors.affiliation: Advanced Device Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
authors.forename: R S
authors.initials: RS
authors.lastname: Deacon
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hartinger
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Herrmann
authors.affiliation: Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.|Laboratory for Quantum Limited Devices, Physics Department, Moscow State Pedagogical University, 29 Malaya Pirogovskaya Moscow 119992, Russia.
authors.forename: T M
authors.initials: TM
authors.lastname: Klapwijk
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Maier
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ames
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Brüne
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Gould
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Oiwa
authors.affiliation: Advanced Device Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishibashi
authors.affiliation: Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tarucha
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Buhmann
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: L W
authors.initials: LW
authors.lastname: Molenkamp