Polarized heat current generated by quantum pumping in two-dimensional topological insulators

F. Ronetti, M. Carrega, D. Ferraro, J. Rech, T. Jonckheere, T. Martin, and M. Sassetti
Phys. Rev. B 95, 115412 – Published 8 March 2017

Abstract

We consider the transport properties of a two-dimensional topological insulator in a double quantum point contact geometry in the presence of a time-dependent external field. In the proposed setup an external gate is placed above a single constriction and it couples only with electrons belonging to the top edge. This asymmetric configuration and the presence of an ac signal allow for a quantum pumping mechanism, which, in turn, can generate finite heat and charge currents in an unbiased device configuration. A microscopic model for coupling with the external time-dependent gate potential is developed and the induced finite heat and charge currents are investigated. We demonstrate that in the noninteracting case, heat flow is associated with a single spin component, due to the helical nature of the edge states, and therefore a finite and polarized heat current is obtained in this configuration. The presence of ee interchannel interactions strongly affects the current signal, lowering the degree of polarization of the system. Finally, we also show that separate heat and charge flows can be achieved, varying the amplitude of the external gate.

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  • Received 24 November 2016
  • Revised 6 February 2017

DOI:https://doi.org/10.1103/PhysRevB.95.115412

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

F. Ronetti1,2,3, M. Carrega4, D. Ferraro3, J. Rech3, T. Jonckheere3, T. Martin3, and M. Sassetti1,2

  • 1Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, I-16146 Genova, Italy
  • 2CNR-SPIN, Via Dodecaneso 33, I-16146 Genova, Italy
  • 3CNRS, CPT, Aix Marseille Université, Université de Toulon, Marseille, France
  • 4NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy

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Issue

Vol. 95, Iss. 11 — 15 March 2017

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