Observation of topological order in a superconducting doped topological insulator

L. Andrew Wray, Su Yang Xu, Yuqi Xia, Yew San Hor, Dong Qian, Alexei V. Fedorov, Hsin Lin, Arun Bansil, Robert J. Cava, M. Zahid Hasan

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    Abstract

    Experimental observation of topological order in three-dimensional bulk solids has recently led to a flurry of research activity 1-21 . Unlike the two-dimensional electron gas or quantum Hall systems, three-dimensional topological insulators can harbour superconductivity and magnetism, making it possible to study the interplay between topologically ordered phases and broken-symmetry states. One outcome of this interplay is the possible realization of Majorana fermions-quasiparticles that are their own antiparticles-on topological surfaces, which is of great interest in fundamental physics 9-13,22-24 . Here we present measurements of the bulk and surface electron dynamics in Bi 2 Se 3 doped with copper with a transition temperature T c up to 3.8 K, observing its topological character for the first time. Our data show that superconductivity occurs in a bulk relativistic quasiparticle regime where an unusual doping mechanism causes the spin-polarized topological surface states to remain well preserved at the Fermi level of the superconductor where Cooper pairing takes place. These results suggest that the electron dynamics in superconducting Bi 2 Se 3 are suitable for trapping non-Abelian Majorana fermions. Details of our observations constitute important clues for developing a general theory of topological superconductivity in doped topological insulators.

    Original languageEnglish (US)
    Pages (from-to)855-859
    Number of pages5
    JournalNature Physics
    Volume6
    Issue number11
    DOIs
    StatePublished - Nov 2010

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    ASJC Scopus subject areas

    • Physics and Astronomy(all)

    Cite this

    Wray, L. A., Xu, S. Y., Xia, Y., Hor, Y. S., Qian, D., Fedorov, A. V., Lin, H., Bansil, A., Cava, R. J., & Hasan, M. Z. (2010). Observation of topological order in a superconducting doped topological insulator. Nature Physics, 6(11), 855-859. https://doi.org/10.1038/nphys1762