Fractional ac Josephson effect in p and dwave superconductors
Abstract
For certain orientations of Josephson junctions between two p_xwave or two dwave superconductors, the subgap Andreev bound states produce a 4πperiodic relation between the Josephson current I and the phase difference φ: Iproptosin(φ/2). Consequently, the ac Josephson current has the fractional frequency eV/hbar, 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 swave and triplet p_xwave, as well as between chiral p_x± ip_ywave superconductors.
 Publication:

European Physical Journal B
 Pub Date:
 February 2004
 DOI:
 10.1140/epjb/e2004000664
 arXiv:
 arXiv:condmat/0210148
 Bibcode:
 2004EPJB...37..349K
 Keywords:

 74.50.+r;
 74.70.Kn;
 74.72.h;
 74.70.Pq;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Organic superconductors;
 Cuprate superconductors;
 Ruthenates;
 Condensed Matter  Superconductivity
 EPrint:
 v. 5: minor update of references in proofs