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 - or -wave-like superconducting gaps, the result being sensitive to the magnitude of the total number density of pairs at which BEC occurs and becomes possible already for a moderately anisotropic -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.

Keywords:

• pseudogap
• preformed pairs
• Fermi arcs
• gap symmetry.

Acknowledgements

We thank D.M. Eagles for numerous comments. TAM thanks the Institute of Physics of Azerbaijan for granting him academic leave at Baskent University in Ankara, Turkey and MdeLl thanks UNAM-DGAPA-PAPIIT (Mexico) for its support via grant IN102014.

Notes

Permanent address: Institute of Physics, Academy of Sciences of Azerbaijan, 370143 Baku, Azerbaijan.