Description

2009/12/18,   Jean-Bernard Bru (UPV/EHU, IKERBASQUE)

Place: Sala de Seminarios del Departamento de Física Teórica e Historia de la Ciencia
Time: 12h.
Title: Effect of a Locally Repulsive Interaction on s-wave Superconductors

Abstract
In collaboration with W. de Siqueira Pedra, we analyze the thermodynamic impact of the Coulomb repulsion on s-wave superconductors via a rigorous study of equilibrium and ground states of the strong coupling BCS-Hubbard Hamiltonian. I will explain that the one-site electron repulsion can favor superconductivity at fixed chemical potential by increasing the critical temperature and/or the Cooper pair condensate density. The Meissner effect is also shown to be rather generic but I will also discuss the feasibility of coexistence of superconducting and ferromagnetic phases, for instance near half-filling and at strong repulsion. Additionnally, our proof of a superconductor-Mott insulator phase transition implies a rigorous explanation of the necessity of doping insulators to create superconductors.