title: Induced superconductivity in the three-dimensional topological insulator HgTe.
abstract: A strained and undoped HgTe layer is a three-dimensional topological insulator, in which electronic transport occurs dominantly through its surface states. In this Letter, we present transport measurements on HgTe-based Josephson junctions with Nb as a superconductor. Although the Nb-HgTe interfaces have a low transparency, we observe a strong zero-bias anomaly in the differential resistance measurements. This anomaly originates from proximity-induced superconductivity in the HgTe surface states. In the most transparent junction, we observe periodic oscillations of the differential resistance as a function of an applied magnetic field, which correspond to a Fraunhofer-like pattern. This unambiguously shows that a precursor of the Josephson effect occurs in the topological surface states of HgTe.
authors.affiliation: Physikalisches Institut, EP3, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Luis
authors.initials: L
authors.lastname: Maier
authors.forename: Jeroen B
authors.initials: JB
authors.lastname: Oostinga
authors.forename: Daniel
authors.initials: D
authors.lastname: Knott
authors.forename: Christoph
authors.initials: C
authors.lastname: Brüne
authors.forename: Pauli
authors.initials: P
authors.lastname: Virtanen
authors.forename: Grigory
authors.initials: G
authors.lastname: Tkachov
authors.forename: Ewelina M
authors.initials: EM
authors.lastname: Hankiewicz
authors.forename: Charles
authors.initials: C
authors.lastname: Gould
authors.forename: Hartmut
authors.initials: H
authors.lastname: Buhmann
authors.forename: Laurens W
authors.initials: LW
authors.lastname: Molenkamp