Unusual electronic structure in underdoped cuprate superconductors

Abstract

The underdoped cuprate superconductors are characterized by the opening of the pseudogap, while such an aspect of the pseudogap effect should be reflected in the low-energy electronic structure (LEES). Here the effect of the pseudogap on LEES in the underdoped cuprate superconductors is investigated within the kinetic-energy-driven superconductivity. The strong coupling of the electrons with the spin excitation induces the pseudogap-state in the particle-hole channel and superconducting (SC) state in the particle-particle channel, where the pseudogap and SC gap respectively originate from the electron normal and anomalous self-energies, and are evaluated by taking into account the vertex correction. As a natural consequence of the interplay between the pseudogap-state and SC-state, the SC transition temperature Tc exhibits a dome-like shape of the doping dependence, however, in a striking contrast to Tc in the underdoped regime, the pseudogap crossover temperature T* is much higher than Tc in the underdoped regime, and then it decreases with the increase of doping, eventually disappearing together with Tc at the end of the SC dome. Concomitantly, the spectral weight on the electron Fermi surface (EFS) at around the antinodal region is suppressed strongly by this pseudogap, and then EFS is truncated to form four disconnected Fermi arcs centered around the nodal region with the largest spectral weight located at around the tips of the disconnected Fermi arcs. Moreover, the dip in the peak-dip-hump structure observed in the energy distribution curve and checkerboard charge ordering found in the ARPES autocorrelation are intrinsically connected with the emergence of the pseudogap. The theory therefore indicates that the same spin excitation that governs both the pseudogap-state and SC-state naturally leads to the exotic features of LEES in the underdoped cuprate superconductors.