Superconductivity in the extended hubbard model with more than nearest-neighbour contributions

Abstract

Superconducting phase diagram of the extended Hubbard model supplemented with interaction and hopping terms exceeding the nearest-neighbour distance in range is analysed systematically at different band filling and temperature values in a mean-field approximation. The obtained results clearly emphasize the importance of next-nearest-neighbour terms in developing the main superconducting phases of different symmetries at a given point of the phase diagram; in particular, critical temperatures T_T , zero temperature gap amplitude values Δ₀, Δ₀/T _c ratios, doping and temperature dependences are all strongly influenced by next-nearest-neighbour contributions.