arXiv:cond-mat/0012511 · Physical review. B, Condensed matter
Finite-temperature time-dependent effective theory for the phase field in two-dimensional d -wave neutral superconductors
Sergei G. Sharapov, H. Beck, В. М. Локтев
Abstract
We derive finite-temperature time-dependent effective actions for the phase of the pairing field, which are appropriate for a two-dimensional electron system with both nonretarded d- and s-wave attraction. As for s-wave pairing, the d-wave effective action contains terms with Landau damping, but their structure appears to be different from the s-wave case due to the fact that the Landau damping is determined by the quasiparticle group velocity ${\mathbf{v}}_{g},$ which for d-wave pairing does not have the same direction as the noninteracting Fermi velocity ${\mathbf{v}}_{F}.$ we show that for d-wave pairing the Landau term has a linear low-temperature dependence and in contrast to the s-wave case is important for all finite temperatures. A possible experimental observation of the phase excitations is discussed.