Band filling effects on coherence lengths and penetration depth in the two-orbital negative-U Hubbard model of superconductivity

Abstract

The two-orbital superconducting state is modeled by on-site intra-orbital negative-U Hubbard correlations together with inter-orbital pair-transfer interactions. The critical temperature is mainly governed by intra-orbital attractive interactions and it can pass through an additional maximum as a function of band filling. For the certain number of electrons the clear interband proximity effect is observable in the superconducting state of the band with a smaller gap. The influence of band fillings and orbital site energies on the temperature dependencies of two-component superconductivity coherence lengths and magnetic field penetration depth is analyzed. The presence of proximity effect is probably reflected in the relative temperature behaviour of characteristic lengths.

Physica C (2012) in press

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Cited by in corpus (3)

• Type-1.5 superconductivity in muliband and other multicomponent systems
• Flat band effects on the ground-state BCS-BEC crossover in atomic Fermi gases in a quasi-two-dimensional Lieb lattice
• Shrinking of fluctuation region in a two-band superconductor