Doped high-Tc cuprate superconductors elucidated in the light of zeros and poles of electronic Green's function

TL;DR

This paper investigates the electronic structure of cuprate high-Tc superconductors using advanced theoretical methods, revealing how zeros and poles of Green's functions explain various experimental anomalies and the pseudogap phenomena.

Contribution

It introduces a unified framework based on zeros and poles of Green's functions to understand Mott physics and pseudogap behavior in cuprates, challenging previous symmetry-breaking explanations.

Findings

Identification of non-Fermi-liquid phase caused by topological Fermi surface transition

Reproduction of experimental spectral features such as Fermi arcs and waterfalls

Demonstration that pseudogap structure varies with energy relative to the Fermi level

Abstract

We study electronic structure of hole- and electron-doped Mott insulators in the two-dimensional Hubbard model to reach a unified picture for the normal state of cuprate high-Tc superconductors. By using a cluster extension of the dynamical mean-field theory, we demonstrate that structure of coexisting zeros and poles of the single-particle Green's function holds the key to understand Mott physics in the underdoped region. We show evidence for the emergence of non-Fermi-liquid phase caused by the topological quantum phase transition of Fermi surface by analyzing low-energy charge dynamics. The spectra calculated in a wide range of energy and momentum reproduce various anomalous properties observed in experiments for the high-Tc cuprates. Our results reveal that the pseudogap in hole-doped cuprates has a d-wave-like structure only below the Fermi level, while it retains non-d-wave structure with a fully opened gap above the Fermi energy even in the nodal direction due to a zero surface extending over the entire Brillouin zone. In addition to the non-d-wave pseudogap, the present comprehensive identifications of the spectral asymmetry as to the Fermi energy, the Fermi arc, and the back-bending behavior of the dispersion, waterfall, and low-energy kink, in agreement with the experimental anomalies of the cuprates, do not support that these originate from (the precursors of) symmetry breakings such as the preformed pairing and the d-density wave fluctuations, but support that they are direct consequences of the proximity to the Mott insulator. Several possible experiments are further proposed to prove or disprove our zero mechanism.