Title
s- and d-wave superconductivity in a two-band model
Date Issued
01 October 2016
Access level
open access
Resource Type
journal article
Author(s)
Continentino M.A.
Thomas C.
Lacroix C.
Instituto Militar de Engenharia
Publisher(s)
Academic Press Inc.
Abstract
Superconductivity in strongly correlated systems is a remarkable phenomenon that attracts a huge interest. The study of this problem is relevant for materials such as the high Tc oxides, pnictides and heavy fermions. In this work we study a realistic model that includes the relevant physics of superconductivity in the presence of strong Coulomb correlations. We consider a two-band model, since most of these correlated systems have electrons from at least two different atomic orbitals coexisting at their Fermi surface. The Coulomb repulsion is taken into account through a local repulsive interaction. Pairing is considered among quasi-particles in neighboring sites and we allow for different symmetries of the order parameter. In order to deal with the strong local correlations, we use the well known slave boson approach that has proved very successful for this problem. Here we are interested in obtaining the zero temperature properties of the model, specifically its phase diagram and the existence and nature of superconducting quantum critical points. We show that these can arise by increasing the mixing between the two bands. Since this can be controlled by external pressure or doping, our results have a direct relation with experiments. We show that the superconductor-to-normal transition can be either to a metal, a correlated metal or to an insulator. Also we compare the relative stability of s and d-wave paired states for different regions of parameter space and investigate the BCS–BEC crossover in the two-band lattice model as function of the strength of the pairing interaction.
Start page
257
End page
272
Volume
373
Language
English
OCDE Knowledge area
Física nuclear Física de partículas, Campos de la Física
Scopus EID
2-s2.0-84979496785
Source
Annals of Physics
ISSN of the container
00034916
Sponsor(s)
D.R. would like to thank the APQ1 Grant No. E-26/111.360/2014 from FAPERJ. M.A.C. would like to thank the Brazilian agencies, FAPERJ , Grant CNE E-26/201.370/2014 and CNPq , Grant 304402/2015-0 for financial support to this work. C.T. acknowledges the financial support of the Brazilian agency Capes for the Grant No. BJT 06/2013 . We acknowledge the financial support of Capes-Cofecub (project Ph 664 10). We would like to thank also Professor Pedro Sacramento for many enlightening discussions. The numerical calculations were performed with the aid of the cluster Ada located at the Laboratório de Física Computacional from IF-UFRGS.
Sources of information: Directorio de Producción Científica Scopus