Theories of anomalous metallic state and Mott trasition

反常金属态和莫特转变理论

基本信息

批准号：
07237102
负责人：
IMADA Masatoshi
金额：
$ 32.77万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
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/en/grant/KAKENHI-PROJECT-07237102/
关键词：
Mott transition transition metal oxide strongly correlated slectron systems cuprate high-TィイD2cィエD2 superconductors quantum critical phenomena orbital degenerary effect incoherent metals non-fermi liquid ハバ-ド模型 t-J模型高温超伝導異常金属反強磁

项目摘要

Theoretical studies of our project on d-electron systems near Mott-insulator-metal transitions have reached a number of achievements. The central subject of our project is metal-insulator transitions or Mott transitions, where we have found a new universality class with a large dynam-ical exponent. We have found that strong momentum dependent renormalization induces singular renormalization. The anomalous feature of the transition is successfully described by synergy effects between spin/orbital fluctuations and momentum degeneracy. With our clarification of singular momentum dependence due to low dimensionality and resultant incoherent charge dynamics, theoretical understanding of the quantum phase transition for the Mott phenomena has entered a new stage. Another important subject in our research was studies on complex properties in d-electron systems. For instance, in Mn oxides, entanglement and interplay among strong cor-relation effects, spin/orbital degeneracy, Jahn-Teller effect … More have been studied in a realistic way as much as possible. Through first principles methods and model calculations, experimental results on spin/orbital/charge orderings and lattice distortions in metals and insulators have successfully been compared. Studies on cuprate superconductors have also made progress. Various approaches such as slave boson methods in the t-J models, 1/N expansion, spin fluctuation theory and numerical methods for correlated fermions have been applied to two-dimensional models with many new pro-posals and concepts to interpret experimental results. Although the consensus on the mechanism of superconductivity has not been reached yet, models to describe the Mott insulator, underdoped and overdoped metals have been proposed on a unified framework. Important progress in under-standing on quantum magnetism in the Mott insulator has also been achieved, especially on the competition between the singlet spin-gapful and the antiferromagnetic phases. Ladder compounds have also been studied intensively. Less

我们项目对Mott-Insulator-Metal跃迁附近的D-电子系统的理论研究已取得了许多成就。我们项目的中心主题是金属 - 绝缘体过渡或Mott Transitions，在那里我们找到了具有较大动态质量指数的新通用类。我们发现，强动量依赖性的重归化会导致奇异的翻新。过渡的异常特征通过自旋/轨道波动与动量退化之间的协同作用成功地描述了。通过澄清由于低维和导致不相互电的电荷动力学引起的奇异动量依赖性的澄清，对Mott现象的量子相变的理论理解已经进入了一个新阶段。我们研究中的另一个重要主题是对D-电子系统中复杂性质的研究。例如，在MN氧化物中，强烈的COR关系效应，自旋/轨道变性，Jahn-Teller效应之间的纠缠和相互作用，尽可能地以现实的方式研究了更多。通过第一原理方法和模型计算，已成功比较了金属和绝缘子中自旋/轨道/电荷订购和晶格扭曲的实验结果。关于库酸酯超导体的研究也取得了进步。 T-J模型中的从属玻色子方法，例如1/N扩展，自旋波动理论和相关费物的数值方法已应用于具有许多新的pro-Posals和概念来解释实验结果的二维模型。尽管尚未达成关于超导性机制的共识，但已经在统一框架上提出了描述莫特绝缘子，不足和超额金属的模型。也已经取得了对莫特绝缘子中量子磁性的理解的重要进展，尤其是在单线旋转巨大和抗磁磁相之间的竞争中。梯子化合物也进行了深入研究。较少的