arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.04951cond-mat.str-elcond-mat.supr-conphysics.chem-ph
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基于密度矩阵嵌入理论的三带哈伯德模型基态phase diagram

Ground-state phase diagram of the three-band Hubbard model from density matrix embedding theory

Zhi-Hao Cui, Chong Sun, Ushnish Ray, Bo-Xiao Zheng, Qiming Sun, Garnet Kin-Lic Chan

摘要:

利用密度矩阵嵌入理论,我们确定了三带哈伯德模型的基态相图。我们研究了原子尺度性质的反铁磁(AFM)和超导(SC)订单,明确包括氧自由度。所有参数化的模型显示AFM和SC阶段,但AFM秩序与掺杂的衰减是太慢的实验相图相比,并进一步,AFM和SC秩序的共存发生在所有参数集。局部磁矩完全集中在铜位点。磁相图对$Δ_{pd}$和$t_{pp}$特别敏感,并且在所谓的最小模型参数化中,电荷转移间隙$Δ_{pd}$的现有估计似乎太大。电子掺杂侧的相图是定性不同的空穴掺杂侧,我们发现一个不寻常的双峰结构中的SC在全模型参数化。在原子尺度上检查SC顺序,在更大规模的$d_{x^2 - y^2}$波SC配对顺序之间的Cu-Cu和O-O,我们还观察到本地$p_{x (y)}$ [或$d_{xz (yz)}$ ]对称调制的对密度的Cu-O键。我们的工作突出了一些功能,出现在一个三波段与一个波段的图片,在新的原子尺度SC订单的氧自由度的作用,并重新评估当前参数化的三波段哈伯德模型的必要性。

英文摘要:

We determine the ground-state phase diagram of the three-band Hubbard model across a range of model parameters using density matrix embedding theory. We study the atomic-scale nature of the antiferromagnetic (AFM) and superconducting (SC) orders, explicitly including the oxygen degrees of freedom. All parametrizations of the model display AFM and SC phases, but the decay of AFM order with doping is too slow compared to the experimental phase diagram, and further, coexistence of AFM and SC orders occurs in all parameter sets. The local magnetic moment localizes entirely at the copper sites. The magnetic phase diagram is particularly sensitive to $Δ_{pd}$ and $t_{pp}$, and existing estimates of the charge transfer gap $Δ_{pd}$ appear too large in so-called minimal model parametrizations. The electron-doped side of the phase diagram is qualitatively distinct from hole-doped side and we find an unusual two-peak structure in the SC in the full model parametrization. Examining the SC order at the atomic scale, within the larger scale $d_{x^2 - y^2}$-wave SC pairing order between Cu-Cu and O-O, we also observe a local $p_{x (y)}$ [or $d_{xz (yz)}$]-symmetry modulation of the pair density on the Cu-O bonds. Our work highlights some of the features that arise in a three-band versus one-band picture, the role of the oxygen degrees of freedom in new kinds of atomic-scale SC orders, and the necessity of re-evaluating current parametrizations of the three-band Hubbard model.

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