Gutzwiller charge phase diagram of cuprates, including electron–phonon coupling effects

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-π π ( , )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 order in YBa 2 Cu 3 O δ − 7including Kohn anomalies, and suggestions of competition between one-and two-q-vector nesting.

High-order Van Hove singularities in cuprates and related high-Tc superconductors

“…The dispersion in Fig. 4 looks unusual because the electronic susceptibility contains nonanalytic features (at T = 0) due to Fermi surface nesting, which also show up in Kohn anomalies of phonons [27]. Interestingly, we find that both the Mexican hat and drumhead (flat-band) dispersions exist in Bosonic systems and give rise to the highorder VHSs similar to shown in Fig.…”

High-Tc superconductors as a New Playground for High-order Van Hove singularities and Flat-band Physics

“…The dispersion in Fig. 3 looks unusual because the electronic susceptibility contains nonanalytic features at T = 0 due to Fermi surface nesting, which also show up in Kohn anomalies of phonons [25]. Interestingly, we find that both the Mexican hat and drumhead (flat-band) dispersions exist in Bosonic systems and give rise to high-order VHSs similar to the electronic case shown in Fig.…”

Entropic Origin of Pseudogap Physics and a Mott-Slater Transition in Cuprates

“…We calculate χ 0 based on the dressed dispersion Z = Z 0 , assuming a doping-independent Z = 0.5. We use a single-band model of the cuprates, working in a purely magnetic sector, with the Hubbard U controlling all fluctuations; there is a competition in this model between near-nodal and antinodal nesting (ANN) which mimics the SDW-CDW competition in cuprates, sharing the same nesting vectors 22 32 .…”

“…The CDW phase, in particular, has stimulated considerable interest13141516171819202122. Many of these phases, including superconductivity, seem to appear at temperatures well below the pseudogap temperature T * , so the exact relation between the pseudogap and these other phases remains elusive.…”

“…Evidence is growing that the ‘pseudogap phase’ found in cuprates is home to one or more competing phases, including a variety of stripe, spin-, or charge-density wave (S/CDW) phases 1 2 3 4 5 6 7 8 9 10 11 12 . The CDW phase, in particular, has stimulated considerable interest 13 14 15 16 17 18 19 20 21 22 . Many of these phases, including superconductivity, seem to appear at temperatures well below the pseudogap temperature T * , so the exact relation between the pseudogap and these other phases remains elusive.…”