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Fractional Solitons in Excitonic Josephson Junctions

The Josephson effect is especially appealing to physicists because it reveals macroscopically the quantum order and phase. In excitonic bilayers the effect is even subtler due to the counterflow of supercurrent as well as the tunneling between layers (interlayer tunneling). Here we study, in a quant...

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Autores principales: Hsu, Ya-Fen, Su, Jung-Jung
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625147/
https://www.ncbi.nlm.nih.gov/pubmed/26511770
http://dx.doi.org/10.1038/srep15796
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author Hsu, Ya-Fen
Su, Jung-Jung
author_facet Hsu, Ya-Fen
Su, Jung-Jung
author_sort Hsu, Ya-Fen
collection PubMed
description The Josephson effect is especially appealing to physicists because it reveals macroscopically the quantum order and phase. In excitonic bilayers the effect is even subtler due to the counterflow of supercurrent as well as the tunneling between layers (interlayer tunneling). Here we study, in a quantum Hall bilayer, the excitonic Josephson junction: a conjunct of two exciton condensates with a relative phase ϕ(0) applied. The system is mapped into a pseudospin ferromagnet then described numerically by the Landau-Lifshitz-Gilbert equation. In the presence of interlayer tunneling, we identify a family of fractional sine-Gordon solitons which resemble the static fractional Josephson vortices in the extended superconducting Josephson junctions. Each fractional soliton carries a topological charge Q that is not necessarily a half/full integer but can vary continuously. The calculated current-phase relation (CPR) shows that solitons with Q = ϕ(0)/2π is the lowest energy state starting from zero ϕ(0) – until ϕ(0) > π – then the alternative group of solitons with Q = ϕ(0)/2π − 1 takes place and switches the polarity of CPR.
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spelling pubmed-46251472015-11-03 Fractional Solitons in Excitonic Josephson Junctions Hsu, Ya-Fen Su, Jung-Jung Sci Rep Article The Josephson effect is especially appealing to physicists because it reveals macroscopically the quantum order and phase. In excitonic bilayers the effect is even subtler due to the counterflow of supercurrent as well as the tunneling between layers (interlayer tunneling). Here we study, in a quantum Hall bilayer, the excitonic Josephson junction: a conjunct of two exciton condensates with a relative phase ϕ(0) applied. The system is mapped into a pseudospin ferromagnet then described numerically by the Landau-Lifshitz-Gilbert equation. In the presence of interlayer tunneling, we identify a family of fractional sine-Gordon solitons which resemble the static fractional Josephson vortices in the extended superconducting Josephson junctions. Each fractional soliton carries a topological charge Q that is not necessarily a half/full integer but can vary continuously. The calculated current-phase relation (CPR) shows that solitons with Q = ϕ(0)/2π is the lowest energy state starting from zero ϕ(0) – until ϕ(0) > π – then the alternative group of solitons with Q = ϕ(0)/2π − 1 takes place and switches the polarity of CPR. Nature Publishing Group 2015-10-29 /pmc/articles/PMC4625147/ /pubmed/26511770 http://dx.doi.org/10.1038/srep15796 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Hsu, Ya-Fen
Su, Jung-Jung
Fractional Solitons in Excitonic Josephson Junctions
title Fractional Solitons in Excitonic Josephson Junctions
title_full Fractional Solitons in Excitonic Josephson Junctions
title_fullStr Fractional Solitons in Excitonic Josephson Junctions
title_full_unstemmed Fractional Solitons in Excitonic Josephson Junctions
title_short Fractional Solitons in Excitonic Josephson Junctions
title_sort fractional solitons in excitonic josephson junctions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625147/
https://www.ncbi.nlm.nih.gov/pubmed/26511770
http://dx.doi.org/10.1038/srep15796
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