Fractional ac Josephson effect in p- and d-wave superconductors

H. J. Kwon, K. Sengupta, V. M. Yakovenko

Research output: Contribution to journalArticlepeer-review


For certain orientations of Josephson junctions between two p x-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4π-periodic relation between the Josephson current I and the phase difference φ: I ∝ sin(φ/2). Consequently, the ac Josephson current has the fractional frequency eV/ℏ, where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction. We also study junctions between singlet s-wave and triplet px-wave, as well as between chiral px ± ipy-wave superconductors.

Original languageEnglish (US)
Pages (from-to)349-361
Number of pages13
JournalEuropean Physical Journal B
Issue number3
StatePublished - Feb 2004
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Fractional ac Josephson effect in p- and d-wave superconductors'. Together they form a unique fingerprint.

Cite this