Effective action approach to the Leggett's mode in two-band superconductors
Institut de Physique, Université de Neuchâtel, 2000 Neuchâtel, Switzerland
2 Bogolyubov Institute for Theoretical Physics, Metrologicheskaya Str. 14-b, Kiev, 03143, Ukraine
Corresponding author: a Sergei.Sharapov@unine.ch
Published online: 19 November 2002
We investigate a collective excitation (Leggett's mode) corresponding to small fluctuations of the relative phase of two condensates in two-band superconductor using the effective “phase only” action. We consider the possibility of observing Leggett's mode in MgB2 superconductor and conclude that for the known at present values of the two-band model parameters for MgB2 Leggett's mode arises above the two-particle threshold.
PACS: 74.20.Fg – BCS theory and its development / 11.10.Wx – Finite-temperature field theory
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002