Superconductivity in the Extended Hubbard Model with More Than Nearest-Neighbour Contributions

TL;DR

This paper systematically analyzes the superconducting phase diagram of an extended Hubbard model with interactions beyond nearest neighbors, highlighting the crucial role of next-nearest neighbor terms in determining superconducting properties.

Contribution

It introduces a comprehensive mean-field analysis of the extended Hubbard model including further-range interactions, emphasizing their impact on superconducting phases and critical parameters.

Findings

Next-nearest neighbor terms significantly influence superconducting phase emergence.

Superconducting properties such as $T_c$, $ riangle_0$, and their ratios are affected by extended interactions.

Different superconducting symmetries can coexist depending on the extended interaction range.

Abstract

Superconducting phase diagram of the extended Hubbard model supplemented with interaction and hopping terms exceeding nearest neighbour distance in range is analysed systematically at different band-filling and temperature values in a mean-field approximation. The obtained results clearly underline the importance of next-nearest neighbour terms in developing the main superconducting properties of the model system. In particular, the emergence of superconducting phases of different symmetry at a given point of the phase diagram, critical temperatures $T_c$, zero temperature gap amplitude values $\Delta_{0}$, $\Delta_{0}/T_{c}$ ratios, doping and temperature dependences are all strongly influenced by next-nearest neighbour contributions.