Exciton Condensation and Charge Fractionalization in a Topological Insulator Film

B. Seradjeh, J. E. Moore, and M. Franz
Phys. Rev. Lett. 103, 066402 – Published 7 August 2009

Abstract

An odd number of gapless Dirac fermions is guaranteed to exist at a surface of a strong topological insulator. We show that in a thin-film geometry and under external bias, electron-hole pairs that reside in these surface states can condense to form a novel exotic quantum state which we propose to call “topological exciton condensate” (TEC). This TEC is similar in general terms to the exciton condensate recently argued to exist in a biased graphene bilayer, but with different topological properties. It exhibits a host of unusual properties including a stable zero mode and a fractional charge ±e/2 carried by a singly quantized vortex in the TEC order parameter.

  • Figure
  • Received 10 February 2009

DOI:https://doi.org/10.1103/PhysRevLett.103.066402

©2009 American Physical Society

Authors & Affiliations

B. Seradjeh1, J. E. Moore2,3, and M. Franz4

  • 1Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
  • 2Department of Physics, University of California, Berkeley, California 94720, USA
  • 3Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
  • 4Department of Physics and Astronomy, University of British Columbia,Vancouver, BC, Canada V6T 1Z1

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Issue

Vol. 103, Iss. 6 — 7 August 2009

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