Quasiparticle interference patterns in a topological superconductor

Aaron Farrell, Maxime Beaudry, M. Franz, and T. Pereg-Barnea
Phys. Rev. B 91, 134510 – Published 20 April 2015

Abstract

In light of recent proposals to realize a topological superconductor on the surface of strong topological insulators, we study impurity and vortex scattering in two-dimensional topological superconductivity. We develop a theory of quasiparticle interference in a model of the surface of a three-dimensional strong topological insulator with a pairing term added. We consider a variety of different scatterers, including magnetic and nonmagnetic impurity as well as a local pairing order parameter suppression associated with the presence of a vortex core. Similar to the case of a surface of a three-dimensional topological insulator without pairing, our results for nonmagnetic impurity can be explained by the absence of back scattering, as expected for a Dirac cone structure. In the superconducting case, doping away from the Dirac point leads to a doubling of the contours of constant energy. This is in contrast to the unpaired case where the chemical potential simply adds to the bias voltage and shifts the energy. This doubling of contours results in multiplying the number of possible scattering processes in each energy. Interestingly, we find that some processes are dominant in the impurity case while others are dominant in the vortex case. Moreover, the two types of processes lead to a different dependence on the chemical potential.

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  • Received 12 February 2015
  • Revised 8 April 2015

DOI:https://doi.org/10.1103/PhysRevB.91.134510

©2015 American Physical Society

Authors & Affiliations

Aaron Farrell1, Maxime Beaudry1,2, M. Franz3, and T. Pereg-Barnea1

  • 1Department of Physics and Centre for the Physics of Materials, McGill University, Montreal, Quebec, Canada
  • 2Département d'Informatique, Université de Montréal, Montreal, Quebec, Canada
  • 3Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada

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Issue

Vol. 91, Iss. 13 — 1 April 2015

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