Unusual electronic structure in underdoped cuprate superconductors

The underdoped cuprate superconductors are characterized by the opening of the normal-state pseudogap, while such an aspect of the normal-state pseudogap effect should be reflected in the low-energy electronic structure. Here the effect of the normal-state pseudogap on the low-energy electronic structure in the underdoped cuprate superconductors is investigated within the framework of the kinetic-energy-driven superconductivity. The strong coupling of the electrons with the spin excitation induces the normal-state pseudogap-state in the particle-hole channel and superconducting (SC) state in the particle–particle channel, where the normal-state 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 normal-state pseudogap-state and SC-state, the SC transition temperature $T_c$ exhibits a dome-like shape of the doping dependence, however, in a striking contrast to $T_c$ in the underdoped regime, the normal-state pseudogap crossover temperature $T^{\ast }$ is much higher than $T_c$ in the underdoped regime, and then it decreases with the increase of doping, eventually disappearing together with $T_c$ 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 normal-state 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 normal-state pseudogap. The theory therefore indicates that the same spin excitation that governs both the normal-state pseudogap-state and SC-state naturally leads to the exotic features of the low-energy electronic structure in the underdoped cuprate superconductors.