Shapiro steps as a direct probe of ±s -wave symmetry in multigap superconducting Josephson junctions

Yukihiro Ota, Masahiko Machida, Tomio Koyama

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20 Citations (Scopus)


We theoretically study the Shapiro steps in a hetero-Josephson junction made of a single-gap superconductor and a two-gap one. We find that an anomalous dc Josephson current is induced by tuning the frequency of an applied microwave to the Josephson-Leggett mode frequency, which creates an extra step structure in the I-V characteristics besides the conventional Shapiro steps. The step heights at the resonance voltages exhibit an alternate structure of a large and small value reflecting the gap symmetry of the two-gap superconductor. In the ±s -wave case in which the two gaps have opposite signs in the two-gap superconductor the steps with odd index are enhanced, whereas in the s -wave case the ones with even index have larger values. The existence of the fractional Shapiro steps is also predicted.

Original languageEnglish
Article number140509
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number14
Publication statusPublished - 2010 Oct 26
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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