Pseudogap Phenomena and Phase Diagram in the Two-Band Hubbard Model
Pseudogap Phenomena and Phase Diagram in the Two-Band Hubbard Model
复制标题
二能带哈伯德模型中的赝能隙现象和相图
DOI：
10.1143/jpsj.70.1214
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发表时间：
2001
影响因子：
1.7
通讯作者：
Y. Kuroda
中科院分区：
文献类型：
--
作者：
A. Kobayashi;A. Tsuruta;T. Matsuura;Y. Kuroda
高温超导材料（HTSC）具有霍尔系数中的赝能隙、1/ T 1 T、态密度等反常性质。首先，考虑到Cu位点d电子之间强烈的在位排斥作用，我们得到了具有超交换相互作用J s 的准粒子，其带宽趋于为零，即随着δ趋于零，系统进入绝缘体。准粒子对应于Zhang-Rice单线态。 J s 大于带宽，结合系统的二维特性，会引起强烈的反铁磁涨落（AFF）和超导涨落（SCF）。我们处理 FLEX 近似中 AFF 的影响和自洽 t 矩阵近似中 SCF 的影响，结果表明，随着 T 从 T > T sg 减小，欠掺杂区域的波动在 T 0 处开始增加，并且在 T > T sg 时 AFF 主导 SCF，而在 T < T sg 时 SCF 主导。这种波动的交叉导致......
High- T c superconducting materials (HTSC) have anomalous properties such as the pseudogap in the Hall coefficient, 1/ T 1 T and the density of states etc. First, including the effects of strong on-site repulsion between d-electrons at Cu-sites, we obtain quasi-particles with superexchange interaction J s , whose band-width tends to reach zero, i.e., the system goes to the insulator, as δ tends to reach zero. The quasi-particles correspond to Zhang-Rice singlet states. J s larger than the band width combined with the two-dimensional characteristic of the system induces strong antiferromagnetic fluctuations (AFF) and superconducting fluctuations (SCF). We treat effects of the AFF in the FLEX approximation and those of the SCF in the self-consistent t -matrix approximation to show that both fluctuations in the underdoped region start to increase at T 0 as T decreases from T ≫ T c , and that the AFF dominate the SCF at T > T sg , while the SCF dominate at T < T sg . This cross-over of the fluctuations causes...