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arXiv 1806.01465cond-mat.str-el
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哈伯德模型中的超导电性及其与电荷条纹和次近邻跳跃t'的相互作用

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

Hong-Chen Jiang, Thomas P. Devereaux

摘要:

我们报道了空穴掺杂浓度为$δ=12.5\%$的四柱轻掺杂哈伯德模型的大尺度密度矩阵重整化群研究。通过保持大量的状态长的系统尺寸,我们能够揭示超导性和电荷和自旋密度波阶之间的微妙的相互作用可调通过次近邻跳跃t '。对于有限的t ',基态与Luther-Emery液体的基态一致,具有“半填充”电荷条纹,具有幂律超导和波长$λ=1/2δ$的电荷密度波相关性,但具有短程自旋相关性。这与t '= 0的情况形成直接对比,在t'= 0的情况下,超导相关性呈指数下降,而电荷和自旋密度调制占主导地位。我们的研究结果表明,一个强大的长程超导性的路线涉及不稳定的绝缘电荷条纹在掺杂哈伯德模型。

英文摘要:

We report a large-scale density-matrix renormalization group study of the lightly doped Hubbard model on 4-leg cylinders at hole doping concentration $δ=12.5\%$. 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 $λ=1/2δ$, 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.

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