Abstract

We study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads. We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a setup provided that edges contain at least one magnetic impurity. The finite polarization appears even in the fully classical regime and is therefore robust to dephasing. There is also a quantum magnetic field-tunable contribution to the polarization, which shows sharp identical Aharonov-Bohm resonances as a function of magnetic flux—with the period hc/2e—and survives at relatively high temperature. We demonstrate that this tunneling interferometer can be described in terms of ensemble of flux-tunable qubits giving equal contributions to conductance and spin polarization. The number of active qubits participating in the charge and spin transport is given by the ratio of the temperature and the level spacing. The interferometer can effectively operate at high temperature and can be used for quantum calculations. In particular, the ensemble of qubits can be described by a single Hadamard operator. The obtained results open wide avenue for applications in the area of quantum computing.

Details

Title
Coherent spin transport through helical edge states of topological insulator
Author
Niyazov, R A 1   VIAFID ORCID Logo  ; Aristov, D N 1   VIAFID ORCID Logo  ; Yu, Kachorovskii V 2   VIAFID ORCID Logo 

 Ioffe Institute, St. Petersburg, Russia (GRID:grid.423485.c) (ISNI:0000 0004 0548 8017); St. Petersburg State University, Department of Physics, St. Petersburg, Russia (GRID:grid.15447.33) (ISNI:0000 0001 2289 6897); NRC ‘Kurchatov Institute’, Petersburg Nuclear Physics Institute, Gatchina, Russia (GRID:grid.430219.d) (ISNI:0000 0004 0619 3376) 
 Ioffe Institute, St. Petersburg, Russia (GRID:grid.423485.c) (ISNI:0000 0004 0548 8017); CENTERA Laboratories, Institute of High Pressure Physics, Polish Academy of Sciences, Warsaw, Poland (GRID:grid.425122.2) (ISNI:0000 0004 0497 7361) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20573960
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2471560618
Copyright
© The Author(s) 2020. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.