Are Preformed Cooper Pairs The Cause For The Pseudogap in Superconductors?

Abstract

A weak-coupling scenario wherein bosonic preformed electron pairs emerge upon cooling from two-electron correlations can explain the pseudogap phase consisting of segments where a Bogoliubov-like energy-momentum relation gapped spectrum alternates with a normal ungapped one. Bose-Einstein condensation (BEC) of preformed pairs interacting with the background fermions leads to either

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- or

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-wave-like superconducting gaps, the result being sensitive to the magnitude of the total number density of pairs

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at which BEC occurs and becomes possible already for a moderately anisotropic

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-wave pairing of fermions repelling each other via isotropic coulombic forces. The present model is compatible with the coexistence of pseudogap and of superconductivity phenomena.