Electromagnetic Response of a Vortex in Layered Superconductors
M. Eschrig, J. A. Sauls and D. Rainer
- Address: Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
- Date: May 23, 1998
- Comment: 8 pages, 6 figures
Physical Review B 60, 10447 (1999)
We calculate the response of a vortex core in a layered superconductor to a.c. electromagnetic fields with
frequencies ω ≲ 2Δ/ℏ.
In this frequency range the response is dominated by order parameter collective modes which are coupled to
the vortex-core bound states of Caroli, de Gennes and Matricon. Our calculations show that a vortex core
has a more complex and richer dynamics than predicted by previous theories.
The a.c. field drives an oscillating, nearly homogeneous supercurrent in the direction of the electric field,
superimposed with a dissipative current flow which has a dipolar spatial structure. The order parameter response
at low frequencies is an approximately rigid collective motion of the vortex structure perpendicular to the
external field. This structure becomes strongly deformed at frequencies of order ω ≳ 0.5 Δ/ℏ.
Coupling of the vortex-core bound states to collective modes of the order parameter at low frequencies leads to
substantial enhancement of the dissipation near the vortex-center well above that of the normal-state.