Gutzwiller Charge Phase Diagram of Cuprates, including Electron-Phonon Coupling Effects

TL;DR

This paper investigates the phase diagram of hole-doped cuprates by incorporating electron-electron and electron-phonon interactions in the Hubbard model, revealing charge order driven by Fermi surface nesting consistent with experimental observations.

Contribution

It introduces a Hubbard model with phonon coupling to analyze charge order and phase behavior in cuprates, highlighting the role of Fermi surface nesting and electron-phonon interactions.

Findings

Charge degrees of freedom activate at low doping levels.

Charge order driven mainly by Fermi surface nesting.

Results align with experimental evidence of charge density waves.

Abstract

Besides significant electronic correlations, high-temperature superconductors also show a strong coupling of electrons to a number of lattice modes. Combined with the experimental detection of electronic inhomogeneities and ordering phenomena in many high-T_c compounds, these features raise the question as to what extent phonons are involved in the associated instabilities. Here we address this problem based on the Hubbard model including a coupling to phonons in order to capture several salient features of the phase diagram of hole-doped cuprates. Charge degrees of freedom, which are suppressed by the large Hubbard U near half-filling, are found to become active at a fairly low doping level. We find that possible charge order is mainly driven by Fermi surface nesting, with competition between a near-(pi,pi) order at low doping and antinodal nesting at higher doping, very similar to the momentum structure of magnetic fluctuations. The resulting nesting vectors are generally consistent with photoemission and tunneling observations, evidence for charge density wave (CDW) order in YBa_2Cu_3O_{7-delta} including Kohn anomalies, and suggestions of competition between one- and two-q-vector nesting.