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 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 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.
@article{arxiv.1210.4320,
title = {Induced superconductivity in the three-dimensional topological insulator HgTe},
author = {Luis Maier and Jeroen B. Oostinga and Daniel Knott and Christoph Bruene and Pauli Virtanen and Grigory Tkachov and Ewelina M. Hankiewicz and Charles Gould and Hartmut Buhmann and Laurens W. Molenkamp},
journal= {arXiv preprint arXiv:1210.4320},
year = {2012}
}
Comments
Accepted for publication in Physical Review Letters