The superconducting gap in the Hubbard model and the two gap energy scales in high-Tc cuprates

Abstract

Recent excperiments (ARPES, Raman) suggest the presence of two distinct energy gaps in high-Tc superconductors (HTSC), exhibiting different doping dependences. Results of a variational cluster approach to the superconducting state of the two-dimensional Hubbard model are presented which show that this model qualitatively describes this gap dichotomy: One gap (antinodal) increases with less doping, a behavior long considered as reflecting the general gap behavior of the HTSC. On the other hand, the near-nodal gap does even slightly decrease with underdoping. An explanation of this unexpected behavior is given which emphasizes the crucial role of spin fluctuations in the pairing mechanism.

4 pages, 5 figures, revised version to be published in Phys. Rev. Lett

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• Dual fermion approach to the two-dimensional Hubbard model: Antiferromagnetic fluctuations and Fermi arcs
• Crossover between BCS Superconductor and Doped Mott Insulator of d-wave Pairing State in Two-Dimensional Hubbard Model
• Nodal/Antinodal Dichotomy and the Two Gaps of a Superconducting Doped Mott Insulator
• Phase diagram and single-particle spectrum of CuO${}_2$ layers within a variational cluster approach to the 3-band Hubbard model
• The doping-driven evolution of the superconducting state of a doped Mott insulator: a key for the high temperature superconductivity
• Evolution of the gaps through the cuprate phase-diagram
• Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime
• CDMFT+HFD : an extension of dynamical mean field theory for nonlocal interactions applied to the single band extended Hubbard model
• Single-Particle Dispersion and Density of States of the Half-Filled 2D Hubbard Model