Josephson supercurrent through a topological insulator surface state

M. Veldhorst, M. Snelder, M. Hoek, T. Gang, V. Goduru, X. Wang, U. Zeitler, Wilfred Gerard van der Wiel, H. Hilgenkamp, Alexander Brinkman

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The long-sought yet elusive Majorana fermion(1) is predicted to arise from a combination of a superconductor and a topological insulator(2-4). An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)-topological insulator (Bi2Te3)-superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov-de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface state. This surface state is attributed to mediate the ballistic Josephson current despite the fact that the normal state transport is dominated by diffusive bulk conductivity. The lateral Nb-Bi2Te3-Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions(5).
Original languageEnglish
Pages (from-to)417-421
Number of pages5
JournalNature materials
Volume11
Issue number5
DOIs
Publication statusPublished - 2012

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Keywords

  • METIS-286919
  • IR-83573

Cite this

Veldhorst, M., Snelder, M., Hoek, M., Gang, T., Goduru, V., Wang, X., ... Brinkman, A. (2012). Josephson supercurrent through a topological insulator surface state. Nature materials, 11(5), 417-421. https://doi.org/10.1038/NMAT3255