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Theoretical Study of Nested Spin Fluctuations

嵌套自旋涨落的理论研究

基本信息

批准号：
07640477
负责人：
MIYAKE Kazumasa
金额：
$ 1.28万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640477/
关键词：
Nested Spin Fluctuations Cuprate high-T_c Superconductors Anomalous Metallic Phase near the Mott Transition Mott Transition in the Intermediate Coupling Regime Spin-Gap Behaviors Itinerant-Localized Duality Model V_2O_3 URu_2Si_2 量子臨界点擬

项目摘要

Through this three years project, it has been shown that the anomalous properties of high-T_c cuprates, such as spin-gap behaviors and spin-charge separation aspects, can be understood in a unified way by taking into account the effects of nested spin-fluctuations on the basis of the Fermi liquid theory. Namely, the origin of such anomalous behaviors has been shown to be attributed to the fact that the spectral weight of coherent spin fluctuations decreases in the low-energy regime because the Fermi surface of the quasiparticles is inevitably nested as the antiferromagnetic Mott insulating state is approached. At the same time, it has been pointed out that the incoherent part of spin fluctuations also plays a crucial role in order to understand these anomalous behaviors consistently.It was also shown that the anomalous behaviors of V_2O_3, which had been considered to be a typical example exhibiting the Mott transition, can be understood as those originating from the nested spin-fluctu … More ations.It was shown, on the basis of the Gutzwiller treatment of d-p model with reasonable values of parameters, that the high-T_c cuprates are the materials belonging to the intermediate coupling regime and their origin of Mott transition should be attributed to the antiferromagnetic correlations accompanied by the nesting of the Fermi surface.A microsopic justification of the Itinerant-Localized Duality Model, which had been offering the basis of a theory of nested spin-fluctuations in strongly correlated metals, was given by means of the skeleton-expansion method of Luttinger-Ward.The anomalous properties of weak magnetism of URu_2Si_2 was shown to be understood as a moment-induced mechanism of the crystal-field singlet ground state of f^2-configuration of U ion together with the nesting effect of a part of the Fermi surface. In particular, it was derived naturally that the magnetic-field dependence of T_N, the Neel temperature, and m (0), the ordered moment at T=0, are scaled by apparently different magnitudes of magnetic field. Less

通过这三年的工作，我们发现，在费米液体理论的基础上，考虑嵌套自旋涨落的影响，可以统一地理解高T_c铜氧化物的反常性质，如自旋能隙行为和自旋-电荷分离现象。也就是说，这种异常行为的起源已被证明是归因于这样一个事实，即相干自旋涨落的谱权重在低能区减少，因为准粒子的费米面是不可避免地嵌套作为反铁磁莫特绝缘态的接近。同时指出，自旋涨落的非相干部分对理解这些反常行为也起着至关重要的作用，并指出V_2O_3的反常行为可以理解为自旋涨落的嵌套行为，而V_2O_3是Mott跃迁的典型例子 ...更多信息通过对d-p模型的Gutzwiller处理和合理的参数值，指出高T_c铜氧化物是属于中间耦合区的材料，其Mott相变的起源应归因于反铁磁关联和费米面的嵌套。它为强关联金属中的嵌套自旋涨落理论提供了基础，用Luttinger-Ward的介子展开方法，给出了URu_2Si_2弱磁性的反常性质，并将其解释为f^2-的晶场单重基态的矩诱导机制的U离子的配置以及费米面的一部分的嵌套效应。特别地，自然地导出了Neel温度T_N和T=0时的有序矩m（0）与磁场的关系，它们与明显不同的磁场大小成比例关系。少