The doping-driven evolution of the superconducting state of a doped Mott insulator: a key for the high temperature superconductivity

Abstract

High-temperature superconductors at zero doping can be considered strongly correlated two-dimensional Mott insulators. The understanding of the connection between the superconductor and the Mott insulator hits at the heart of the high-temperature superconducting mechanism. In this paper we investigate the zero-temperature doping-driven evolution of a superconductor towards the Mott insulator in a two dimensional electron model, relevant for high temperature superconductivity. To this purpose we use a cluster extension of dynamical mean field theory. Our results show that a standard (BCS) d-wave superconductor, realized at high doping, is driven into the Mott insulator via an intermediate state displaying non-standard physical properties. By restoring the translational invariance of the lattice, we give an interpretation of these findings in momentum space. In particular, we show that at a finite doping a strong momentum-space differentiation takes place: non-Fermi liquid and insulating-like (pseudogap) character rises in some regions (anti-nodes), while Fermi liquid quasiparticles survive in other regions (nodes) of momentum space. We describe the consequence of these happenings on the spectral properties, stressing in particular the behavior of the superconducting gap, which reveals two distinct nodal and antinodal energy scales as a function of doping. We propose a description of the evolution of the electronic structure while approaching the Mott transition and compare our results with tunneling experiments, photoemission and magnetotransport on cuprate materials.