Fractional Solitons in Excitonic Josephson Junctions

Ya Fen Hsu, Jung-Jung Su*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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 • 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 ‰= ‰• 0 /2€ is the lowest energy state starting from zero • 0 - until • 0 ‰> ‰€ - then the alternative group of solitons with Q ‰= ‰• 0 /2€ ‰' ‰1 takes place and switches the polarity of CPR.

Original languageEnglish
Article number15796
JournalScientific reports
StatePublished - 29 Oct 2015

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