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 high-temperature superconductors. Within our model, the appearance of FC presents a boundary separating the region of a strongly interacting electron liquid from the region of a strongly correlated electron liquid. We study the superconductivity of a strongly correlated liquid and show that under certain conditions, the superconductivity vanishes at temperatures $T>T_c\simeq T_{node}$, with the superconducting gap being smoothly transformed into a pseudogap. As the result, the pseudogap occupies only a part of the Fermi surface. The gapped area shrinks with increasing the temperature and vanishes at $T=T^{\ast }$. The single-particle excitation width is also studied. The quasiparticle dispersion in systems with FC can be represented by two straight lines characterized by the respective effective masses $M_{FC}^{\ast }$ and $M_L^{\ast }$, and intersecting near the binding energy that is of the order of the superconducting gap. It is argued 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 this phase transition can be considered as kinetic energy driven.

16 pages, 3 figures, minor grammatical changes, revised and accepted by JETP

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Cited by in corpus (6)

• Quasiparticle picture of high temperature superconductors in the frame of Fermi liquid with the fermion condensate
• Two Types of the Effective Mass Divergence and the Grüneisen Ratio in Heavy Fermion Metals
• Fermion Condensation Quantum Phase Transition versus Conventional Quantum Phase Transitions
• Fermion-condensation quantum phase transition in high temperature superconductors
• Relationships between the superconducting gap, pseudogap and transition temperature in High-T_c superconductors
• Quantum critical point in high-temperature superconductors