Electron Self-Organizations and Transport Phenomena in High-Tc Cuprate Superconductors

高温铜酸盐超导体中的电子自组织和输运现象

• 批准号: 16340112
• 负责人: ANDO Yoichi
• 金额: $ 11.1万
• 依托单位: Osaka University (2007)Central Research Institute of Electric Power Industry (2004-2006)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16340112/
• 关键词: High-Tc Superconductor; Self-Organization; Transport Properties; High-Quality Single Crystals; Charge Stripes; Fermi Arc; Thermal Conductivity; Hall Coefficient; 擬ギャップ; 磁場誘起絶縁体状態; 電荷移動励起; 電子ドープ; スピン励起; 磁気抵抗; チェッカーボード秩序

It is recognized that some sort of electron self-organization occurs in high-Tc cuprate superconductors due to strong electron correlations. Also, it seems likely that in cuprates the electron self-organization phenomena lie behind their peculiar electronic states such as unusual insulating normal state under high magnetic fields or intrinsic inhomogeneity of the superconducting gap. This project has clarified various aspects of the electron self-organization phenomena in cuprates through experiments using high-quality single crystals, in particular their transport properties measurements under extreme conditions. Principal results are the following:1. We discovered the existence of "magic doping fractions" for charge ordering in La_2-X_Sr_xCuO_4, and showed that a checkerboard model consistently explains the observed fractions.2. Extensive measurements of ultra-low-temperature thermal conductivity of YBa_2Cu_3O_y, La_2-x_Sr-xCuO_4, and Bi_2Sr_2CaCu_xO_<8+δ> revealed a breakdown of the "universal thermal conductivity", which is generically expected for d-wave BCS superconductors. This breakdown is apparently related to the peculiar superconducting gap inhomogeneity in cuprates.3. Through the ultra-low-temperature measurements of transport properties of nonsuperconducting YBa_2Cu_3O_y, where a self-organized resistivity anisotropy is known to exist, we elucidated that the electron self-organized state is inherently insulating when it is nonsuperconducting. Moreover, we found that this insulating state is characterized by the peculiar log(1/T) resistivity divergence.4. We elucidated that the charge transfer energy in the CuO_2 plane can be obtained from the temperature dependence of the Hall coefficient measured up to 1000 K. Furthermore, we showed that the Hall coefficient data can be used for disentangling the phase-separated nature of La_2-x_Sr_xCuO_4 in the superconducting doping regime.

人们认识到，由于强的电子关联，在高Tc铜氧化物超导体中发生了某种电子自组织。此外，在铜氧化物中，电子自组织现象可能隐藏在它们特殊的电子态背后，例如在高磁场下不寻常的绝缘正常态或超导带隙的内在不均匀性。该项目通过使用高质量单晶的实验，特别是极端条件下的输运性质测量，阐明了铜酸盐中电子自组织现象的各个方面。主要结果如下：1.发现了La_（2-x）Sr_xCu_（O_4）中存在电荷有序的“魔掺杂分数”，并证明了棋盘格模型对所观察到的分数的解释.对YBa_2Cu_3O_y，La_2-x_Sr-xCuO_4和Bi_2Sr_2CaCu_xO_（8+δ）的超低温热导率的测量表明，d波BCS超导体的“普适热导率”被打破。这种击穿显然与铜氧化物中特有的超导能隙不均匀性有关.通过对非超导YBa_2Cu_3O_y的输运性质的超低温测量，阐明了电子自组织态在非超导时是固有绝缘的。此外，我们还发现这种绝缘状态具有特殊的log（1/T）电阻率发散特性.我们阐明了CuO_2面内的电荷转移能可由1000 K以下的霍尔系数随温度的变化关系求得。此外，我们还指出，霍尔系数数据可以用来解释La_2-x_Sr_xCuO_4超导掺杂体系的相分离性质。

项目成果

Low-temperature vortex liquid in La 2− x Sr x CuO 4

• DOI: 10.1038/nphys563
• 发表时间: 2007-02
• 期刊: Nature Physics
• 影响因子: 19.6
• 作者: Lu Li;J. Checkelsky;S. Komiya;Y. Ando;N. Ong

Crystal structure and high-field magnetism of La2 Cu O4

• DOI: 10.1103/physrevb.73.144513
• 发表时间: 2006-01
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Reehuis;C. Ulrich;K. Prokeš;A. Gozar;A. Gozar;Girsh Blumberg;S. Komiya;Y. Ando;Philip Pattison;Philip Pattison;B. Keimer

High Energy Spin Excitations in Electron-Doped Superconductor Pr_0.88LaCe_0.12CuO_<4-δ> with T_c=21K

T_c=21K 的电子掺杂超导体 Pr_0.88LaCe_0.12CuO_<4-δ> 中的高能自旋激发

• 发表时间: 2006
• 期刊: Physical Review Letters 96巻
• 作者: A.D.LaForge;W.J.Padilla;K.S.Burch;Z.Q.Li;S.V.Dordevic;Kouji Segawa;Yoichi Ando;D.N.Basov;J. E. Sonier;A. D. LaForge;S.Ono;Hye Jung Kang;X.F.Sun;Stephen D.Wilson
• 通讯作者: Stephen D.Wilson

High Energy Spin Excitations in Electron-Doped Superconducting Pr_0.88LaCe_0.12CuO_4-δwith T_c=21K

电子掺杂超导Pr_0.88LaCe_0.12CuO_4-δ中T_c=21K的高能自旋激发

• 发表时间: 2006
• 期刊: Physical Review Letters 97巻・1号
• 作者: S.D.Wilson;Shiliang Li;P.Dai;Wei Bao;Jae-Ho Chung;H.J.Kang;Seung-Hun Lee;Seiki Komiya;Yoichi Ando;Qimiao Si;Stephen D.Wilson
• 通讯作者: Stephen D.Wilson

Electron-carrier doping to Y123 system by La substitution for Ba

La取代Ba对Y123体系进行电子载流子掺杂

• 发表时间: 2007
• 作者: Kouji Segawa;Yoichi Ando
• 通讯作者: Yoichi Ando