Suppressed superexchange interactions in the cuprates by bond-stretching oxygen phonons

Abstract

We study a multi-orbital Hubbard-Su-Schrieffer-Heeger model for the one-dimensional (1D) corner-shared cuprates in the adiabatic and nonadiabatic limits using the exact diagonalization and determinant quantum Monte Carlo methods. Our results demonstrate that lattice dimerization can be achieved only over a narrow range of couplings slightly below a critical coupling gc at half-filling. Beyond this critical coupling, the sign of the effective hopping changes, and the lattice becomes unstable. We also examine the model's temperature-dependent uniform magnetic susceptibility and the dynamical magnetic susceptibility and compare them to the results of an effective spin-1/2 Heisenberg model. In doing so, we numerically demonstrate that the lattice fluctuation induced by the e-ph interaction suppresses the effective superexchange interaction. Our results elucidate the effect of bond-stretching phonons in the parent cuprate compounds in general and are particularly relevant to 1D cuprates, where strong e-ph interactions have recently been inferred.

A hybrid Monte Carlo study of bond-stretching electron-phonon interactions and charge order in the bismuthate family of superconductors

“…To this end, we take Ω 0 = 60 meV, which is typical for the bond-stretching optical oxygen phonons in most oxides [32,43]. Note that in all of our simulations, we have confirmed that the displacements of the oxygen atoms remain small enough that the effective hopping never changes sign, ensuring the validity of a linear SSH coupling [44,45].…”

Ground state and spectral properties of the doped one-dimensional optical Hubbard-Su-Schrieffer-Heeger model

“…In this limit, the carriers are separated into a single region of half-filled sites with a bond-wave ordering surrounded by regions of empty sites. Finally, another study of a multi-orbital Hubbard-SSH model in the strongly correlated high-density limit at half-filling also observed lattice instabilities in the strong coupling limit [18].…”

“…This microscopic coupling mechanism thus modulates the electron's kinetic energy as opposed to its potential energy as in the canonical Holstein [2] or Fröhlich [3] models. While the SSH model in one-dimension (1D) has been studied extensively since its inception, interest in SSH-like interactions 1 in a broader class of models and systems has recently surged [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. This activity has been driven by the realization that such interactions can lead to several novel effects, including the stabilization of nontrivial topological states [19,20,23,24] and Dirac points [8], novel bipolaronic charge-density wave [10,16,21] and bond-wave [15,22] orderings, and the formation of mobile bipolarons [9].…”

“…Nevertheless, only a few non-perturbative studies of the Hubbard-SSH model have been carried out. For example, while the model has been studied in one-and two-dimensions [15,18,[45][46][47], these studies focused on half-filling, where an interesting interplay between the e-ph interaction and antiferromagnetism has been observed. Ref.…”

Superconducting Phases of the Square-Lattice Extended Hubbard Model

“…Moreover, recent ARPES experiments on 1D cuprate chains have revealed a sizeable attractive Coulomb interaction between nearest-neighbor (NN) electrons [40]. Although not as strong as the on-site Coulomb repulsion, this attractive interaction is comparable to the electron hopping integral, and thereby should not be ignored [41]. The structural similarities among the cuprates also suggest that attractive NN interaction may exist in quasi-2D cuprate materials in general.…”