Oscillatory eigenmodes and stability of one and two arbitrary fractional vortices in long Josephson 0-κ junctions
Abstract
We investigate theoretically the eigenmodes and the stability of one and two arbitrary fractional vortices pinned at one and two κ phase discontinuities in a long Josephson junction. In the particular case of a single κ discontinuity, a vortex is spontaneously created and pinned at the boundary between the 0 and κ regions. In this work we show that only two of four possible vortices are stable. A single vortex has an oscillatory eigenmode with a frequency within the plasma gap. We calculate this eigenfrequency as a function of the fractional flux carried by a vortex. For the case of two vortices, pinned at two κ discontinuities situated at some distance a from each other, splitting of the eigenfrequencies occurs. We calculate this splitting numerically as a function of a for different possible ground states. We also discuss the presence of a critical distance below which two antiferromagnetically ordered vortices form a strongly coupled “vortex molecule” that behaves as a single object and has only one eigenmode.
- Publication:
-
Physical Review B
- Pub Date:
- March 2005
- DOI:
- 10.1103/PhysRevB.71.104518
- arXiv:
- arXiv:cond-mat/0410340
- Bibcode:
- 2005PhRvB..71j4518G
- Keywords:
-
- 74.50.+r;
- 85.25.Cp;
- 74.20.Rp;
- 63.20.Pw;
- Tunneling phenomena;
- point contacts weak links Josephson effects;
- Josephson devices;
- Pairing symmetries;
- Localized modes;
- Condensed Matter - Superconductivity
- E-Print:
- submitted to Phys. Rev. B ()