CONTROL OF STRONGLY CORRELATED 1D CHAIN COMPOUNDS DOPED WITH CHARGE CARRIERS

掺杂载流子的强相关一维链化合物的控制

• 批准号: 10440103
• 负责人: TAKAGI Hidenori
• 金额: $ 3.97万
• 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 (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10440103/
• 关键词: one dimensional chain; Tomonaga Luttinger liquid; magnetic field induced dimensional crossover; Y1248; spin liquid; geometrical frustration; スピネル酸化物; YBa CuO; 結晶成長; 朝永-ラッティンジャー; YBa_2 Cu_4 O_8; 強相関一次元電子系; YBa_2Cu_4O_8; 磁場誘起次元交差; パルス強磁場

This project aims to explore exotic quantum electronic phase in 1 dimensional spin liquids doped with charge carriers. Can Tomonaga-Luttinger liquid be realized ? By introducing external stimulation, can drastic phase change be brought about? With these in mind, we have investigated a cuprate YBa_2Cu_4O_8. YBa_2Cu_4O_8 is unique in that its 1D double chain is remarkably metallic and can be regarded as a doped 1D antiferromagnet. By carefully examining the tranport properties of the metallic double chain, we found novel phenomenon-magnetic field induced dimensional crossover. By applying magnetic field, the interchain transport switches from metallic to insulating around a critical magnetic field B=15 T, indicating electrons are confined within chains. We have proposed a microscopic mechanism behind this switching, based on a real space orbit picture discussed by Lebed and Gorkov. By examining the influence of Zn impurity, then, we have given an experimental verification of the real space orbit picture.In the last stage of the project, we have attempted to extend the idea of doped spin liquid from 1D magnet to 3D magnet. We focused on 3D spin liquid realized by a geometrical frustration and explored exotic phenomena produced by charge carrier doping. As an output, we have established the existence of a heavy fermion state in LiV_2O_4 spinel and revealed the intimate connection between the the heavy electron mass and the spin liquid state produced by geometrical frustration.

本项目旨在探索一维掺杂载流子的自旋液体中的奇异量子电子相。Tomonaga-Luttinger液体能实现吗？通过引入外部刺激，能否带来剧烈的相变？有鉴于此，我们研究了一种铜酸盐YBa2Cu4O8。YBa2Cu4O8的独特之处在于它的一维双链具有显著的金属性，可视为掺杂的一维反铁磁体。通过仔细研究金属双链的输运性质，我们发现了新的现象--磁场诱导的空间交叉。通过施加磁场，在临界磁场B=15T附近，链间输运从金属转变为绝缘，这表明电子被限制在链中。我们已经提出了这种转换背后的微观机制，基于Leed和Gorkov讨论的真实空间轨道图像。通过考察锌杂质的影响，我们对真实的空间轨道图像进行了实验验证。在项目的最后阶段，我们尝试将掺杂自旋液体的想法从一维磁体扩展到三维磁体。我们聚焦于通过几何受挫实现的3D自旋液体，并探索了电荷载流子掺杂产生的奇异现象。作为输出，我们证实了LiV_2O_4尖晶石中重费米子态的存在，并揭示了重电子质量与几何受挫产生的自旋液态之间的密切联系。

项目成果

N.E.Hussey,H.T akagi,Y.Iye,S.Tajima,A.I.Rykov,and K.Yoshida: "Charge confinement on the CuO_2 planes in slightly overdoped YBa_2Cu_3O_<7-δ> and the role of metallic chains"Phys.Rev.. B61・10. R6475-R6478 (2000)

N.E. Hussey、H.T akagi、Y.Iye、S. Tajima、A.I. Rykov 和 K. Yoshida：“稍微过量掺杂的 YBa_2Cu_3O_<7-δ> 中 CuO_2 平面上的电荷限制和金属链的作用” B61・10。R6475-R6478（2000）

J.Okamoto, T.Mizokawa, A.Fujimori, I.Hase, M.Nohara, H.Takagi, Y.Takeda, and M.Takano: "Correlation Effects in the Electronic Structure of SrRuO_3"Phys.Rev.B60. 4. 2281-2285 (1999)

J.Okamoto、T.Mizokawa、A.Fujimori、I.Hase、M.Nohara、H.Takagi、Y.Takeda 和 M.Takano：“SrRuO_3 电子结构中的相关效应”Phys.Rev.B60。

N.E.Hussey, H.Takagi, N.Mori, H.Takeshita, Y.Iye, S.Adachi and K.Tanabe: "Vortex Lattice Melting in YBa_2Cu_4O_8 with H//ab"Proc.exactly aligned magnetic fiels effects in low dimensional superconductors, Kyoto. (1998)

N.E.Hussey、H.Takagi、N.Mori、H.Takeshita、Y.Iye、S.Adachi 和 K.Tanabe：“YBa_2Cu_4O_8 中的涡晶格熔化与 H//ab”Proc.低维超导体中精确排列的磁场效应

K.Ohishi, K.Kakuta, J.Akimitsu, W.Higemoto, R.Kadono, R.I.Miller, A.Price, R.F.Kiefl, J.E.Sonier, M.Nohara, H.Suzuki, H.Takagi: "Anomalous Field Dependence of the Vortex-Core Radius and Magnetic Penetration Depth in YNi_2B_2C Probed by μ SR"Physica B. 289

K.Ohishi、K.Kakuta、J.Akimitsu、W.Higemoto、R.Kadono、R.I.Miller、A.Price、R.F.Kiefl、J.E.Sonier、M.Nohara、H.Suzuki、H.Takagi：“反常场依赖性μ SR"Physica B. 289探测YNi_2B_2C中涡核半径和磁穿透深度

T.Yokoya, T.Kiss, T.Watanabe, S.Shin, M.Nohara, H.Takagi, and T.Oguchi: "Ultrahigh-Resolution Photoemission Spectroscopy of Ni Borocarbides : Direct Observatio of the Superconducting Gap and a Change in Gap Anisotropy by Impurity"Phys.Rev.Lett.. 85, 23. 4

T.Yokoya、T.Kiss、T.Watanabe、S.Shin、M.Nohara、H.Takagi 和 T.Oguchi：“Ni 硼碳化物的超高分辨率光电发射光谱：超导间隙和间隙变化的直接观察