Study of electronic inhomogeneity and superconductivity in high-Tc superconductors by scanning tunneling microscopy.

利用扫描隧道显微镜研究高温超导体的电子不均匀性和超导性。

• 批准号: 15340107
• 负责人: KOBAYASHI Norio
• 金额: $ 10.5万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340107/
• 关键词: High-Tc oxide superconductor; Scanning tunneling Microscopy; Local electronic structure; Pseudogap; Vortex structure; Atomic image; impurity state; 銅酸化物超伝導体; 電子状態; YBa_2Cu_3O_y; Pb置換Bi2201; 磁束状態; 超伝導材料; 渦糸状態; 表面電子状態; 不純物効果; 低温物性実験

The aim of this program is to reveal atomic-scale electronic structures of high-Tc oxide superconductors by scanning tunneling microscopy (STM/STS) and to investigate the relationship between the superconductivity and the characteristic electronic structure, such as granular structure composed of the superconducting and pseudogap regions. In this study, we have observed atomic-scale electronic structures of YBa2Cu3Oy (YBCO) and Bi2-xPbxSr2CuOy (Pbx-Bi2201) single crystals with various carrier concentrations as well as macroscopic superconducting properties.1. YBa2Cu3Oy : (1) We have successfully prepared single crystals with different electronic coupling strength between adjacent CuO2 layers by controlling anneal conditions in nitrogen atmosphere and observed 2 to 3 dimensional transformation of the vortex system. (2) Effects of oxygen defects and impurities on the vortex structure and the electronic state have been studied macroscopically and microscopically. (3) One-dimensional elect … More ronic modulations on the BaO layer at low bias voltage have been observed along the Cu-O direction. These modulations are closely related to the electronic inhomogeneity induced by impurities and/or defects.2. Bi2-xPbxSr2CuOy : (1) The temperature and carrier concentration dependences of the superconducting transition temperature Tc and the pseudogap formation temperature T^* have been studied for well prepared Pb substituted Bi2201 single crystals. (2) It has been clarified that there exist two types of pseudogap ; one is related to a precursor effect of superconductivity and another to a strong electron correlation. The latter exist even in the overdoped region. (3) In STM images measured at high bias-voltages above 300 mV, a clear two-dimensional atomic arrangement, which consists of Bi and Pb atoms, has been observed. On the other hand, at low bias-voltages below 150 mV, it has been found that a contrasting density forms into bright patches of 1-3 nm diameters. These results are consistent with the electronic granularity observed in Bi2212. Less

该项目的目的是通过扫描隧道显微镜（STM/STS）揭示高Tc氧化物超导体的原子级电子结构，并研究超导性与特征电子结构（例如由超导组成的颗粒结构）之间的关系。在这项研究中，我们观察到了 YBa2Cu3Oy (YBCO) 和 Bi2-xPbxSr2CuOy 的原子级电子结构。 (Pbx-Bi2201)单晶具有不同的载流子浓度以及宏观超导性能。 1. YBa2Cu3Oy : (1) 通过控制氮气气氛中的退火条件，我们成功制备了相邻 CuO2 层之间具有不同电子耦合强度的单晶，并观察到 ​​2 (2)从宏观和角度研究了氧缺陷和杂质对涡旋结构和电子态的影响。 (3) 在低偏置电压下，沿 Cu-O 方向观察到 BaO 层上的一维电子调制。这些调制与杂质和/或缺陷引起的电子不均匀性密切相关。2． Bi2-xPbxSr2CuOy : (1) 研究了制备良好的 Pb 的超导转变温度 Tc 和赝能隙形成温度 T^* 的温度和载流子浓度依赖性(2) 已经阐明存在两种类型的赝能隙；一种与超导的前体效应有关，另一种与强电子相关性有关。 (3) In。在高于 300 mV 的高偏压下测量的 STM 图像，观察到了由 Bi 和 Pb 原子组成的清晰的二维原子排列，而在低于 300 mV 的低偏压下，观察到了清晰的二维原子排列。 150 mV 时，发现对比密度形成直径为 1-3 nm 的亮斑。这些结果与 Bi2212 中观察到的电子粒度一致。

项目成果

Vortex State in YBa2Cu3Oy Crystals : Vortex Phase Diagram and Tunneling Spectroscopy in Magnetic Field

YBa2Cu3Oy 晶体中的涡旋态：磁场中的涡旋相图和隧道光谱

• 发表时间: 2004
• 期刊: Physica B 346-347
• 作者: M.Wakasugi;M.Wakasugi;T.Suda;M.Wakasugi;M.Wakasugi;T.Nishizaki;M.Wakasugi;T.Naito;T.Suda;K.Kudo;須田 利美;M.Maki;M.Wakasugi;K.Shibata;T.Suda;K.Kudo;T.Suda;T.Naito;T.Suda;M.Maki;T.Suda;K.Shibata;K.Kudo;K.Kudo;N.Kobayashi
• 通讯作者: N.Kobayashi

Quasiparticle spectra and their spatial variation on YBa_2Cu_3O_y by scanning tunneling spectroscopy

YBa_2Cu_3O_y 扫描隧道光谱准粒子谱及其空间变化

• 发表时间: 2003
• 期刊: Physica C 388-389
• 作者: M.Wakasugi;M.Wakasugi;T.Suda;M.Wakasugi;M.Wakasugi;T.Nishizaki;M.Wakasugi;T.Naito;T.Suda;K.Kudo;須田 利美;M.Maki;M.Wakasugi;K.Shibata;T.Suda;K.Kudo;T.Suda;T.Naito;T.Suda;M.Maki;T.Suda;K.Shibata;K.Kudo;K.Kudo;N.Kobayashi;T.Naito;T.Naito;K.Kinoshita;T.Naito;N.Yoneyama;N.Yoneyama;T.Nishizaki;N.Kobayashi;K.Shibata
• 通讯作者: K.Shibata

Vortex Matter Physics in YBa2Cu3Oy Single Crystals

YBa2Cu3Oy 单晶中的涡旋物质物理

• 发表时间: 2005
• 作者: M.Wakasugi;M.Wakasugi;T.Suda;M.Wakasugi;M.Wakasugi;T.Nishizaki;M.Wakasugi;T.Naito;T.Suda;K.Kudo;須田 利美;M.Maki;M.Wakasugi;K.Shibata;T.Suda;K.Kudo;T.Suda;T.Naito;T.Suda;M.Maki;T.Suda;K.Shibata;K.Kudo;K.Kudo;N.Kobayashi;T.Naito;T.Naito;K.Kinoshita;T.Naito;N.Yoneyama;N.Yoneyama;T.Nishizaki;N.Kobayashi;K.Shibata;M.Maki;T.Sasaki;西嵜照和;T.Nishizaki;N.Kobayashi;K Shibata;T.Sasaki;T.Nishizaki;T.Nishizaki;T.Nishizaki;T.Nishizaki
• 通讯作者: T.Nishizaki

M.Maki, T.Nishizaki, N.Kobayashi: "LT-STM Observation of YBa2(Cu1-xZnx)3O7-δ Single Crystals"Physica C. 388・389. 279-280 (2003)

M.Maki、T.Nishizaki、N.Kobayashi：“YBa2(Cu1-xZnx)3O7-δ 单晶的 LT-STM 观察”Physica C. 388・389 (2003)。

Vortex Phase Diagram in Zn-Doped YBa2Cu3Oy Crystals

掺锌 YBa2Cu3Oy 晶体中的涡旋相图

• 发表时间: 2003
• 期刊: J. Low Temp. Phys. 131
• 作者: M.Wakasugi;M.Wakasugi;T.Suda;M.Wakasugi;M.Wakasugi;T.Nishizaki;M.Wakasugi;T.Naito;T.Suda;K.Kudo;須田 利美;M.Maki;M.Wakasugi;K.Shibata;T.Suda;K.Kudo;T.Suda;T.Naito;T.Suda;M.Maki;T.Suda;K.Shibata;K.Kudo;K.Kudo;N.Kobayashi;T.Naito;T.Naito;K.Kinoshita;T.Naito;N.Yoneyama;N.Yoneyama;T.Nishizaki;N.Kobayashi
• 通讯作者: N.Kobayashi