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arXiv 2602.20073cond-mat.str-el
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二维Hubbard模型中磁性、电荷和超导序的共存

Coexisting magnetic, charge, and superconducting orders in the two-dimensional Hubbard model

Max Planck Institute for Solid State Research(马克斯·普朗克固体研究所);Harvard University(哈佛大学)

Robin Scholle, Pietro M. Bonetti, Walter Metzner, Demetrio Vilardi

AI总结:

研究揭示二维Hubbard模型中磁性、电荷和超导序的共存现象,通过重整化群方法探索不同掺杂条件下相变行为。

摘要:

我们对二维反常Hubbard模型进行了重整化平均场研究,重点研究磁性、电荷和超导序的复杂相互作用和可能共存。我们通过利用重整化群框架来捕捉高能波动,改进了传统平均场理论。该方法生成了有效的磁性和d波配对相互作用,并允许在弱和中等相互作用强度下无偏探索共存相。对有效哈密顿量在大有限晶格上的无限制平均场计算结合热力学极限分析,揭示了一个丰富的相图,包含大量共存序的区域。我们发现,在电子掺杂侧,d波超导性与反铁磁序共存。在空穴掺杂侧,超导性与螺旋或条纹磁序共存。在条纹有序区域中,超导序参数是空间调制的,其周期遵循条纹的电荷调制。在van Hove填充以下,配对提供主要的能量收益,而条纹序仅提供少量且因此脆弱的能量降低。

英文摘要:

We perform a renormalized mean-field study of the two-dimensional repulsive Hubbard model, focusing on the intricate interplay and possible coexistence of magnetic, charge, and superconducting orders. We improve on conventional mean-field theory by utilizing a renormalization group framework that captures high-energy fluctuations. This method generates effective magnetic and $d$-wave pairing interactions, and allows for an unbiased exploration of coexisting phases at weak and moderate interaction strengths. Unrestricted mean-field calculations of the effective Hamiltonian on large finite lattices are combined with analyses in the thermodynamic limit, revealing a rich phase diagram with extensive regions of coexisting orders. We find that $d$-wave superconductivity coexists with Néel order on the electron-doped side. On the hole-doped side, superconductivity is found to coexist with spiral or stripe magnetic orders. Within the stripe ordered region, the superconducting order parameter is spatially modulated, with a period that follows the charge modulation of the stripes. Below van Hove filling, pairing provides the primary energy gain, while the stripe order yields only a small, and hence fragile, additional energy lowering.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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