Superconducting phases of the square-lattice extended Hubbard model
Superconducting phases of the square-lattice extended Hubbard model
复制标题
DOI：
10.1103/physrevb.108.064514
复制
发表时间：
2022-06
影响因子：
3.7
通讯作者：
Wei-Chih Chen;Yao Wang;Cheng-Chien Chen
中科院分区：
文献类型：
--
作者：
Wei-Chih Chen;Yao Wang;Cheng-Chien Chen
利用精确对角化方法研究了具有在位U相互作用和最近邻V相互作用的正方格点扩展Hubbard模型。我们表明，非平衡淬火动力学可以帮助确定平衡相变边界，这与保真度度量，动力学结构因子和相关函数的计算相一致。在半填充时，强耦合区的相图包括大正U$处的自旋密度波和d_{x^2-y^2}$波超导，大正（负）V$处的电荷密度波（扩展的s^*$波超导），以及大负U$处的s$波超导，其中V$为零。不同颗粒扇区的能量也有助于确定相分离区域。随着载流子掺杂，电荷涨落导致不同阶数之间的竞争，使得有限尺寸团簇上主导不稳定性的识别变得更加困难。然而，当体系中空穴浓度为37.5%~ 50%时，特别是在与铜氧化物超导体相关的相互作用参数范围内，更奇异的p波超导配对被增强.
We study the square-lattice extended Hubbard model with on-site $U$ and nearest-neighbor $V$ interactions by exact diagonalization. We show that non-equilibrium quench dynamics can help determine the equilibrium phase transition boundaries, which agree with the calculations of fidelity metric, dynamical structure factor, and correlation function. At half filling, the phase diagrams in the strong-coupling regime include spin density wave and $d_{x^2-y^2}$-wave superconductivity at large positive $U$, charge density wave (extended $s^*$-wave superconductivity) at large positive (negative) $V$, and $s$-wave superconductivity at large negative $U$ with vanishing $V$. The energies of different particle sectors also help determine the phase separation region. With carrier doping, charge fluctuation result in strong competition between different orders, making it more difficult to identify the leading instability on finite-size cluster. Nevertheless, the more exotic $p$-wave superconducting pairing is found to be enhanced when the system is heavily overdoped by $37.5\%-50\%$ holes, especially in interaction parameter range relevant to the cuprate superconductors.