Superconductivity in the Hubbard model and its interplay with charge stripes and next-nearest hopping t'

TL;DR

This study uses large-scale density-matrix renormalization group simulations to explore how next-nearest neighbor hopping influences superconductivity and charge order in the doped Hubbard model on 4-leg cylinders, revealing conditions for robust superconductivity.

Contribution

It demonstrates the impact of next-nearest neighbor hopping t' on the emergence of superconductivity and charge stripes in the doped Hubbard model, highlighting a pathway to long-range superconductivity.

Findings

Finite t' leads to Luther-Emery liquid behavior with power-law superconducting correlations.

Zero t' results in exponential decay of superconductivity and dominant charge/spin modulations.

Destabilizing insulating charge stripes may promote robust long-range superconductivity.

Abstract

We report a large-scale density-matrix renormalization group study of the lightly doped Hubbard model on 4-leg cylinders at hole doping concentration $\delta=12.5\%$. By keeping a large number of states for long system sizes, we are able to reveal a delicate interplay between superconductivity and charge and spin density wave orders tunable via next-nearest neighbor hopping t'. For finite t', the ground state is consistent with that of a Luther-Emery liquid, having `half-filled' charge stripes with power-law superconducting and charge-density-wave correlations of wave-length $\lambda=1/2\delta$, but short-range spin correlations. This is in direct contrast to the case with t'=0, where superconducting correlations fall off exponentially while charge- and spin-density modulations are dominant. Our results indicate that a route to robust long-range superconductivity involves destabilizing insulating charge stripes in the doped Hubbard model.