Dissipation-enabled fractional Josephson effect

Doru Sticlet, Jay D. Sau, Anton Akhmerov

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)
28 Downloads (Pure)


The anomalous 4π-periodic ac Josephson effect, a hallmark of topological Josephson junctions, was experimentally observed in a quantum spin Hall insulator. This finding is unexpected due to time-reversal symmetry preventing the backscattering of the helical edge states and therefore suppressing the 4π-periodic component of the Josephson current. Here, we analyze the two-particle inelastic scattering as a possible explanation for this experimental finding. We show that a sufficiently strong inelastic scattering restores the 4π-periodic component of the current beyond the short Josephson junction regime. Its signature is an observable peak in the power spectrum of the junction at half the Josephson frequency. We propose to use the exponential dependence of the peak width on the applied bias and the magnitude of the dc current as means of verifying that the inelastic scattering is indeed the mechanism responsible for the 4π-periodic signal.

Original languageEnglish
Article number125124
Number of pages16
JournalPhysical Review B
Issue number12
Publication statusPublished - 2018


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