Superconductivity in the presence of correlations

• Published in: Physics letters. A 2016-01, Vol.380 (3), p.495-501
• Main Authors: Calegari, E.J., Rodríguez-Núñez, J.J.
• Format: Article
• Language: English
• Subjects: Correlations; Critical temperature; Hubbard model; Superconductivity
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2015.10.060

Following a two-pole approximation for strong correlations in the presence of superconductivity, we investigated the interplay between local repulsion and superconductivity, mainly on Tc, which is the superconducting critical temperature. In addition to correlations, we used a tight-binding band structure that considers hopping beyond the first nearest neighbors. Our approach is based on a doped Mott insulator, which has as its starting point the physics of strong correlations, which produces two Dirac delta functions for the spectral density. We conclude that correlations change the value of Tc,max and the position of this maximum. Integration around the Fermi sea was carried out by including a cutoff frequency, ωd. This work is mainly devoted to a superconductor with an order parameter of s-wave symmetry, which comes from a superconducting pairing potential, V, with V≤0. However, results for d-wave symmetry are also presented. Our results show that a mean-field treatment of correlations is not enough to completely understand these two mechanisms (superconductivity and correlations) where they act simultaneously. •The effects of correlations on superconductivity with s-wave and also dx2−y2-wave symmetry pairing.•Correlations play an important role in strongly correlated superconductors.•A mean-field treatment is not sufficient to adequately describe strongly correlated superconductors.•Correlations change the value of Tc,max.