Quasiparticles in a strongly correlated liquid with the fermion condensate : applications to high temperature superconductors

Quasiparticles in a strongly correlated liquid with the fermion condensate: applications to high temperature superconductors Abstract A model of a strongly correlated electron liquid based on the fermion condensation (FC) is extended to the consideration of high temperature superconductors. Within our model the appearance of FC presents a boundary, separating the region of strongly interacting electron liquid from the region of strongly correlated electron liquid. We study the superconductivity of strongly correlated liquid and show that under certain conditions the superconductivity vanishes at temperatures T > T c ≃ T node , with the superconducting gap being smoothly transformed into a pseudogap. As a result, the pseudogap occupies only a part of the Fermi surface. The gapped area shrinks with increasing temperature and vanishes at T = T *. The single particle excitation width is also studied. The quasiparticle dispersion in systems with FC can be presented with two straight lines, characterizing by effective masses M * F C and M * L , respectively, and intersecting near the binding energy which is of the order of the superconducting gap. It is hoped that this strong change of the quasiparticle dispersion at the binding can be enhanced in underdoped samples because of strengthening the FC influence. The FC phase transition in the presence of the superconductivity is examined, and it is shown that such a phase transition can be considered as kinetic energy driven.