Macroscopic quantum tunneling in multigap superconducting Josephson junctions: Enhancement of escape rate via quantum fluctuations of the Josephson-Leggett mode

Yukihiro Ota, Masahiko Machida, Tomio Koyama

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

We theoretically study the macroscopic quantum tunneling (MQT) in a hetero Josephson junction formed by a conventional single-gap superconductor and a multigap superconductor such as iron-based superconductors and MgB 2. In such a Josephson junction more than one phase difference is defined. We clarify their phase dynamics and construct a theory for the MQT in the multigap Josephson junctions. The dynamics of the phase differences are strongly affected by the Josephson-Leggett mode, which is the out-of-phase oscillation mode of the phase differences. The escape rate is calculated in terms of the effective action renormalized by the Josephson-Leggett mode at zero-temperature limit. We successfully predict drastic enhancement of the escape rate when the frequency of the Josephson-Leggett mode is less than the Josephson-plasma frequency.

Original languageEnglish
Article number060503
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume83
Issue number6
DOIs
Publication statusPublished - 2011 Feb 11

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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