Doped high- T c cuprate superconductors elucidated in the light of zeros and poles of the electronic Green's function
Doped high- T c cuprate superconductors elucidated in the light of zeros and poles of the electronic Green's function
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DOI：
10.1103/physrevb.82.134505
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发表时间：
2010-04
影响因子：
3.7
通讯作者：
S. Sakai;Y. Motome;M. Imada
中科院分区：
文献类型：
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作者：
S. Sakai;Y. Motome;M. Imada
我们在二维Hubbard模型中研究了空穴掺杂和电子掺杂的Mott绝缘体的电子结构，得到了铜酸盐高温超导体正常态的统一图像。通过对动力学平均场理论的集团推广，我们证明了单粒子格林函数零极点共存的结构是理解欠掺杂区域Mott物理的关键。通过对低能电荷动力学的分析，证明了费米面的拓扑量子相变导致了非费米液相的出现。在较宽的能量和动量范围内计算的光谱重现了在实验中观察到的高T_c铜酸盐的各种反常性质。我们的结果表明，空穴掺杂铜酸盐中的伪隙只在费米能级以下具有类d波结构，而由于零面延伸到整个布里渊区，即使在节点方向，它也保持了非d波结构，在费米能级以上有一个完全开放的能隙。除了非d波伪能隙外，目前关于费米能量、费米弧以及色散、瀑布和低能扭结的光谱不对称性的综合识别与铜酸盐的实验异常一致，并不支持这些起源于对称破缺(例如预成对和d密度波涨落)，但支持它们是靠近Mott绝缘体的直接后果。进一步提出了几个可能的实验来证明或反驳我们的零机制。
We study electronic structure of hole- and electron-doped Mott insulators in the two-dimensional Hubbard model to reach a unified picture for the normal state of cuprate high-Tc superconductors. By using a cluster extension of the dynamical mean-field theory, we demonstrate that structure of coexisting zeros and poles of the single-particle Green's function holds the key to understand Mott physics in the underdoped region. We show evidence for the emergence of non-Fermi-liquid phase caused by the topological quantum phase transition of Fermi surface by analyzing low-energy charge dynamics. The spectra calculated in a wide range of energy and momentum reproduce various anomalous properties observed in experiments for the high-Tc cuprates. Our results reveal that the pseudogap in hole-doped cuprates has a d-wave-like structure only below the Fermi level, while it retains non-d-wave structure with a fully opened gap above the Fermi energy even in the nodal direction due to a zero surface extending over the entire Brillouin zone. In addition to the non-d-wave pseudogap, the present comprehensive identifications of the spectral asymmetry as to the Fermi energy, the Fermi arc, and the back-bending behavior of the dispersion, waterfall, and low-energy kink, in agreement with the experimental anomalies of the cuprates, do not support that these originate from (the precursors of) symmetry breakings such as the preformed pairing and the d-density wave fluctuations, but support that they are direct consequences of the proximity to the Mott insulator. Several possible experiments are further proposed to prove or disprove our zero mechanism.