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arXiv · 2308.03846

Attractive Su-Schrieffer-Heeger-Hubbard Model on a Square Lattice Away from Half-Filling

Bo Xing·Chunhan Feng·Richard Scalettar·G. George Batrouni·Dario Poletti
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Abstract

The Su-Schrieffer-Heeger (SSH) model, with bond phonons modulating electron tunneling, is a paradigmatic electron-phonon model that hosts an antiferromagnetic order to bond order transition at half-filling. In the presence of repulsive Hubbard interaction, the antiferromagnetic phase is enhanced, but the phase transition remains first-order. Here we explore the physics of the SSH model with attractive Hubbard interaction, which hosts an interesting interplay among charge order, s-wave pairing, and bond order. Using the numerically exact determinant quantum Monte Carlo method, we show that both charge order, present at weak electron-phonon coupling, and bond order, at large coupling, give way to s-wave pairing when the system is doped. Furthermore, we demonstrate that the SSH electron-phonon interaction competes with the attractive Hubbard interaction and reduces the s-wave pairing correlation.

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Bo Xing, Chunhan Feng, Richard Scalettar, G. George Batrouni, Dario Poletti. 2023-08-07. Attractive Su-Schrieffer-Heeger-Hubbard Model on a Square Lattice Away from Half-Filling. https://doi.org/10.1103/physrevb.108.l161103

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