Disorder Effects in BCS-BEC Crossover Region of Attractive Hubbard Model

Abstract

We study the disorder effects upon superconducting transition temperature T_c and the number of local pairs in attractive Hubbard model within the combined Nozieres - Schmitt-Rink and DMFT+Σapproximations. We analyze the wide range of attractive interaction U, from the weak coupling region, where instability of the normal phase and superconductivity are well described by BCS model, to the limit of strong coupling, where superconducting transition is determined by Bose--Einstein condensation of compact Cooper pairs, forming at temperatures much higher than superconducting transition temperature. It is shown that disorder can either suppress T_c in the weak coupling limit, or significantly enhance T_c in the case of strong coupling. However, in all cases we actually prove the validity of generalized Anderson theorem, so that all changes of T_c are related to change of the effective bandwidth due to disorder. Similarly, disorder effects on the number of local pairs are only due to these band-widening effects.

5 pages, 4 figures

References in corpus (6)

• Many-Body Physics with Ultracold Gases
• The numerical renormalization group method for quantum impurity systems
• Dynamical mean-field theory and numerical renormalization group study of superconductivity in the attractive Hubbard model
• Pseudogaps in Strongly Correlated Metals: Optical Conductivity within the Generalized Dynamical Mean-Field Theory Approach
• Mott-Hubbard Transition and Anderson Localization: Generalized Dynamical Mean-Field Theory Approach
• Interplay of electron-phonon interaction and strong correlations: DMFT+Σstudy

Cited by in corpus (8)

• Attractive Hubbard model with disorder and the generalized Anderson theorem
• Temperature dependence of the upper critical field in disordered Hubbard model with attraction
• Attractive Hubbard Model: Homogeneous Ginzburg - Landau Expansion and Disorder
• Ginzburg - Landau Expansion in BCS - BEC Crossover Region of Disordered Attractive Hubbard Model
• DMFT+Sigma approach to disordered Hubbard model
• Ginzburg - Landau expansion in strongly disordered attractive Anderson - Hubbard model
• Temperature Dependence of Paramagnetic Critical Magnetic Field in Disordered Attractive Hubbard Model
• Ginzburg-Landau expansion and the upper critical field in disordered attractive Hubbard model