Hole superconductivity in Hubbard subbands

T. Domański; G. Litak; K. I. Wysokiński

doi:10.1103/PhysRevB.49.12182

← Back to search

Hole superconductivity in Hubbard subbands

T. Domański, G. Litak, K. I. Wysokiński

DOI 10.1103/PhysRevB.49.12182 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We study the superconducting properties of the system described by the correlated-hopping model in the limit of intermediate and strong correlations. The main effect of the Hubbard term U is reflected in the appearance of the separated Hubbard subbands. The other interaction term Kij in the Hamiltonian introduces the correlation between quasiparticles and for small number of holes in the system leads to the appearance of superconductivity. The superconducting transition temperature hardly changes with U in the approximation we use. We have found the dependence of the superconducting energy gap on temperature T and energy ɛk. It turns out to be a nearly linear function of ɛk. The temperature dependence of the two components of the gap slightly differ from the BCS Δ(T) function. The effective gap to the Tc ratio strongly depends on the carrier concentration n taking on large values for small n (n<0.1) and being close to the BCS value of 1.76 at larger n.