Conductance fingerprint of Majorana fermions in the topological Kondo effect

Martin R. Galpin, Andrew K. Mitchell, Jesada Temaismithi, David E. Logan, Benjamin Béri, and Nigel R. Cooper
Phys. Rev. B 89, 045143 – Published 31 January 2014

Abstract

We consider an interacting nanowire/superconductor heterostructure attached to metallic leads. The device is described by an unusual low-energy model involving spin-1 conduction electrons coupled to a nonlocal spin-12 Kondo impurity built from Majorana fermions. The topological origin of the resulting Kondo effect is manifest in distinctive non-Fermi-liquid (NFL) behavior, and the existence of Majorana fermions in the device is demonstrated unambiguously by distinctive conductance line shapes. We study the physics of the model in detail, using the numerical renormalization group, perturbative scaling, and Abelian bosonization. In particular, we calculate the full scaling curves for the differential conductance in ac and dc fields, onto which experimental data should collapse. Scattering t matrices and thermodynamic quantities are also calculated, recovering asymptotes from conformal field theory. We show that the NFL physics is robust to asymmetric Majorana-lead couplings, and here we uncover a duality between strong and weak coupling. The NFL behavior is understood physically in terms of competing Kondo effects. The resulting frustration is relieved by inter-Majorana coupling which generates a second crossover to a regular Fermi liquid.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
1 More
  • Received 21 December 2013
  • Revised 10 January 2014

DOI:https://doi.org/10.1103/PhysRevB.89.045143

©2014 American Physical Society

Authors & Affiliations

Martin R. Galpin1, Andrew K. Mitchell1, Jesada Temaismithi1, David E. Logan1, Benjamin Béri2,3, and Nigel R. Cooper2

  • 1Department of Chemistry, Physical and Theoretical Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
  • 2TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
  • 3School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 89, Iss. 4 — 15 January 2014

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×