Robust superconducting correlation against intersite interactions in the extended two-leg Hubbard ladder

Abstract

The Hubbard and related models serve as a fundamental starting point in understanding the novel experimental phenomena in correlated electron materials, such as superconductivity, Mott insulator, magnetism. Recent numerical simulations demonstrate that the next-nearest-neighbor hopping t′ plays a key role for the superconductivity. However, the impacts of long-range intersite interactions in such a t′-Hubbard model are less explored. Using the state-of-art density-matrix renormalization group method, we investigate the t′-Hubbard model on a two-leg ladder with the intersite interactions extended to the fourth neighbors. The numerical results show that the quasi-long-range superconducting correlation remains stable under the repulsive intersite interactions and these long-range repulsive interactions only change the ground state quantitatively. In addition, inspired by recent experiments on one-dimensional cuprate chain Ba2−xSrxCuO3+δ, we find that the nearest-neighbor attractive interaction significantly enhances the superconducting correlation when it is comparable to the nearest-neighbor hopping t. Stronger attraction drives the system into an electron-hole phase separation. Finally, we discuss the effects of the on-site interaction on superconductivity.

Source-reported materials — not catalogue approval

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