Quasiparticle interactions in two- and three-dimensional superconductors
Department of Physics, State University of New York,
Buffalo, New York 14260, USA
Accepted: 14 October 1997
I investigate the difference between the quasiparticle properties in two-dimensional (2D) and three-dimensional (3D) s-wave superconductors. Using the original BCS model for the pairing interaction and direct Coulomb interaction I show that quasiparticle interactions lead to a stronger energy dependence in the single-particle self-energies in 2D than in 3D superconductors. This difference arises from the presence of the low-lying collective mode of the order parameter in the 2D case which ensures that oscillator strength in the response function is at low frequencies, . This strong quantitative difference between 2D and 3D superconductors points to the importance of treating quasiparticle interactions in low-dimensional superconductors rather than assuming that renormalizations remain unchanged from the normal state.
PACS: 74.20.Fg – BCS theory and its development / 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 74.80.Dm – Superconducting layer structures: superlattices, heterojunctions, and multilayers
© EDP Sciences, 1997