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

Research output: Contribution to journalArticlepeer-review

328 Scopus citations

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

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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