Anomalous Metallic State near the Mott Transition

莫特转变附近的异常金属态

• 批准号: 07237105
• 负责人: SATO Masatoshi
• 金额: $ 100.29万
• 依托单位: Nagoya University
• 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-07237105/
• 关键词: Mott transition; high temperature superconductivity; anomalous metallic state; spin gap; strongly correlated electrons; 2次元強相関電子系; 超伝導対称性

In the temperature(T) and carrier concentration phase diagram of high-TィイD2cィエD2 Cu oxides, the anomalous metallic phase (AMP), in which various physical properties exhibit unusual behavior can be found in the region near the "half-filled" Mott insulating phase, or in the region T< TィイD20ィエD2 (P) (p*pィイD20ィエD2, T0(pィイD20ィエD2)=ィイD20ィエD2), where p is the concentration of holes doped into the "half-filled" state. The coincidence of the p-region of the AMP with the superconducting p-region clearly indicates that detailed knowledge on this AMP is essentially important for the understanding of the origin(s) of the superconductivity. From this view point experiments have been carried out to study the physical behavior of high- TィイD2cィエD2 oxides and other related systems, where neutron scattering, NMR, angle-resolved photoemission, optical measurements, STM/STS and other various methods have been applied. As the results of the studies, it has been clarified that the anomalous properties in the … More AMP are closely connected with the antiferromagnetic correlation and the singlet formation which begin to grow at around TィイD20ィエD2 with decreasing T. At around the so-called spin-gap temperature TィイD2SGィエD2 (< TィイD20ィエD2), the singlet correlation dominates over the antiferromagnetic one and therefore effects of the spin gap become significant in various quantities. The supercondunting transition is further suppressed down to TィイD2cィエD2 (<TィイD2SGィエD2) in the underdoped region by the fluctuating nature of the orderparaxneter.The physical picture on the singlet formation described above indicates that the origin of the superconductivity is closely related with the large exchange interaction J among the Cu spins and the d-wave symmetry of the order parameter is naturally understood.Besides the studies on high-TィイD2cィエD2 systems, various achievements have been obtained : Superconductivity has been discovered in a doped ladder system under high pressure. Superconductivity which is possibly exotic has also been found is SrィイD22ィエD2RuOィイD24ィエD2. Behavior which indicates the spin-charge separation has been found in quasi one dimensional spin system by angle-resolved photoemission studies. Extensive studies on the metal-insulator transition in transition metal oxides and sulfides have also been carried out. Less

在高温Cu氧化物的温度(T)和载流子浓度相图中，在“半”填充的莫特绝缘附近区域可以发现各种物理性质表现出异常行为的异常金属相(AMP)。相，或在 T< T D20 D2 (P) (p*p D20 D2) 区域， T0(pD20D2)=D20D2)，其中p是掺杂到“半填充”状态的空穴浓度。AMP的p区与超导p区的重合清楚地表明关于该AMP的详细知识。从这个角度来看，对于理解超导性的起源至关重要，已经进行了实验来研究高超导的物理行为。 T2D2氧化物和其他相关系统，其中中子散射、核磁共振、角分辨光电子发射、光学测量、STM/STS和各种其他方法已经被应用，作为研究的结果，已经澄清了......的异常性质。更多的 AMP 与反铁磁相关性和单线态形成密切相关，单线态形成在 T20D20 左右开始随着 T 的降低而增长。当所谓的自旋间隙温度 TiD2SGieD2 (< TiiD20ieD2) 时，单重态相关性优于反铁磁相关性，因此自旋间隙的影响在各种量上变得显着，超导转变在 TiiD2cieD2 (<TiiiD2SGieD2) 中被进一步抑制。欠掺杂区域的波动性质上述单重态形成的物理图景表明，超导性的起源与Cu自旋之间的大交换相互作用J密切相关，有序参数的d波对称性自然是可以理解的。 -TiiD2cieD2系统，已取得各种成就：在高压下的掺杂梯系统中发现了超导性，也发现了可能是奇异的超导性。通过角分辨光电子研究，在准一维自旋系统中发现了表明自旋电荷分离的行为，对过渡金属氧化物和硫化物中的金属-绝缘体转变也进行了广泛的研究。

项目成果

I.Yamada: "Electron Paramagnetic Resonance Governed by the Dzyaloshinsky-Moriya Antisymmetric Exchange Interaction in CuGeO_3" J.Phys,: Condensed Matt.8. 2625-2640 (1996)

I.Yamada：“CuGeO_3 中 Dzyaloshinsky-Moriya 反对称交换相互作用控制的电子顺磁共振”J.Phys，：Condensed Matt.8。

M.Oda: "STM and STS Studies on Superconducting Gap Symmetry of Bi_2Sr_2CaCU_2O_<8+δ>" Physica C. (in press.).

M. Oda：“Bi_2Sr_2CaCU_2O_<8+δ> 超导带隙对称性的 STM 和 STS 研究”Physica C.（正在出版）。

S.Wakimoto: "Two-Dimensional Antiferromagnetic Correlations in the Oxygen-Doped 2-1-4 Type Cuprates" Physica B. 237-238. 91-92 (1997)

S.Wakimoto：“氧掺杂 2-1-4 型铜酸盐中的二维反铁磁相关性”Physica B. 237-238。

S.Tanaka: "Symmetry of the Superconducting Order Parameter of High-Tc Oxides and Consideration of the R-Dependent Tunneling in STM/STS" J.Phys.Soc.Jpn.65. 2212-2219 (1996)

S.Tanaka：“高 Tc 氧化物超导有序参数的对称性以及 STM/STS 中 R 相关隧道效应的考虑”J.Phys.Soc.Jpn.65。

S.Katano: "Pressure Effects on Dimerization in the Spin-Peierls State of CuGeO_3" Phys.Rev.B. 52. 15364-15367 (1995)

S.Katano：“压力对 CuGeO_3 自旋 Peierls 态二聚的影响”Phys.Rev.B。