arXiv:2406.08780 · Physical review. B./Physical review. B
Mean-field study of superconductivity in the t − J square lattice model with three-site hopping
Ke Yang, Qianqian Chen, Lei Qiao, Zheng Zhu
Abstract
It remains an open question whether the two-dimensional single-band pure Hubbard model and its related pure $t\text{\ensuremath{-}}J$ model truly capture the superconducting order in cuprates. Recent numerical studies on this issue have raised a notable disparity in superconducting order between the pure Hubbard model and the pure $t\text{\ensuremath{-}}J$ model. Inspired by these works, we investigate the role of the three-site hopping term in $d$-wave superconductivity, such a term is usually neglected in the effective Hamiltonian of the Hubbard model, although its amplitude is of the same order as the superexchange coupling $J$ in the $t\text{\ensuremath{-}}J$ model. Our slave-boson mean-field solution demonstrates the suppression of $d$-wave superconducting order by incorporating the three-site hopping term, consistent with numerical observations by the density-matrix renormalization group. This suppression could be understood as a result of competition between superexchange interaction and three-site hopping, the former favors $d$-wave pairing while the latter favors $s$-wave pairing. We also discussed its role in quasiparticle dispersion and boson-condensation temperature. Our findings may offer an alternative understanding of the recent numerical contrasting findings in the strong-coupling regime: the absent or weak superconductivity in the pure Hubbard model, while the robust superconductivity in the $t\text{\ensuremath{-}}J$ model without including the three-site hopping term.