Microscopic electronic heterogeneity and its effect on the optical spectrum of high-temperature superconductors

高温超导体微观电子异质性及其对光谱的影响

• 批准号: 15204030
• 负责人: UCHIDA Shin-ichi
• 金额: $ 31.53万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15204030/
• 关键词: high-T_c superconductivity; microscopic heterogeneity; competing orders; optical response; STM; STS; disorder in crystalline lattice; pseudogap phase; Josephson plasma; T_c向上; 電子ガラス; 擬ギャップ; 光学スペクトル; 磁場誘起現象; 相競合; ノード準粒子; 反ノード準粒子; 第2近接ポッピング

We investigated the effect of microscopic heterogeneity on the optical spectrum of high-Tc copper oxide superconductors using various spectroscopic methods, particularly STM/STS, applied to well-controlled single crystalline samples. The major results of the present research are:(1)Elucidation of the roles played by two distinct quasiparticles (QP), nodal and antinodal quasiparticles, in d-wave superconductors. Nodal QP has longer lifetime/coherence which gives rise to the periodic modulations of the local-electronic-density-of-states (LDOS) due to quantum-mechanical interference. On the other hand, antinodal QP is incoherent, and strongly influenced by lattice disorder, playing a major role in the microscopic heterogeneity in high-Tc cuprates.(2)Among disorder in various lattice sites of cuprates, the disorder in the apical oxygen block next to the CuO2 plane is found to most strongly affects the electronic state of the CuO2 plane. This disorder stabilizes a competing order which shows up as a pseudogap in the various spectroscopies. Using a special analysis on the STM/STS result, we revealed that the competing order/the pseudogap phase is a sort of electromic glass.(3)The antinodal QP is intimately related to the c-axis optical spectrum in which the superconducting response appears as a Josephson plasma mode because cuprates are regarded as a series of Josephson junctions along the c-axis. We demonstrated that magnetic fields applied parallel to the CuO2 planes make the Josephson junctions heterogeneous, and, as a consequence, a new Josephson plasma mode appears in the terahertz frequency region. We also showed that the frequency of the new Josephson plasma mode can be tuned by changing the strength of applied magnetic field.

我们研究了微观不均一性对高tc氧化铜超导体光谱的影响，使用各种光谱方法，特别是STM/STS，应用于控制良好的单晶样品。本研究的主要成果有：(1)阐明了两种不同的准粒子——节点准粒子和反节点准粒子在d波超导体中的作用。节点QP具有较长的寿命/相干性，这导致了局域电子态密度（LDOS）由于量子力学干扰而产生的周期性调制。另一方面，反节点QP是非相干的，并且受到晶格无序的强烈影响，在高tc铜酸盐的微观非均质性中起主要作用。(2)在铜酸盐各晶格位的无序中，靠近CuO2平面的顶端氧块的无序对CuO2平面的电子态影响最大。这种无序稳定了在各种光谱中表现为伪间隙的竞争秩序。通过对STM/STS结果的特殊分析，我们发现竞争序/赝隙相是一种电子玻璃。(3)反节点QP与c轴光谱密切相关，其中超导响应表现为约瑟夫森等离子体模式，因为铜酸盐被认为是沿c轴的一系列约瑟夫森结。我们证明了平行于CuO2平面的磁场使约瑟夫森结不均匀，因此，在太赫兹频率区域出现了新的约瑟夫森等离子体模式。我们还证明了新约瑟夫森等离子体模式的频率可以通过改变外加磁场的强度来调节。

项目成果

Comment on "Phase Diagram of La_<2-x>Sr_xCuO_4 Probed in the Infrared : Imprints of Charge Stripe Excitations

评论“红外探测的 La_<2-x>Sr_xCuO_4 相图：电荷条纹激发的印记”

• 发表时间: 2003
• 期刊: Phys. Rev. Lett. 91
• 作者: 杉山博幸;氷鉋楊四郎;S.Tajima et al.
• 通讯作者: S.Tajima et al.

Field-Enhanced Diamagnetism in the Pseudogap State of the Cuprate Superconductor in an Intense Magnetic Field

强磁场中铜超导体赝能隙态的场增强抗磁性

• 发表时间: 2005
• 期刊: Phys.Rev.Lett. 95
• 作者: Ryouji Matsuda,;Akinobu Kanda;Youiti Ootuka;Yayu Wang et al.
• 通讯作者: Yayu Wang et al.

Effect of Disorder Outside the CuO_2 Plane on T_c of Copper Oxide Superconductors

CuO_2面外无序对氧化铜超导体T_c的影响

• 发表时间: 2005
• 期刊: Phys. Rev. Lett. 95
• 作者: E.W.Streed;A.P.Chikkatur;T.L.Gustavson;M.Boyd;Y.Torii;D.Schneble;G.K.Campbell;D.E.Pritchard;W.Ketterle;J.T.Okada;K.Fujita et al.
• 通讯作者: K.Fujita et al.

Dichotomy between nodal and antinodal quasiparticles in underdoped (La2-xSrx)CuO4 superconductors.

• DOI: 10.1103/physrevlett.92.187001
• 发表时间: 2004-03
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: Xingjiang Zhou;T. Yoshida;D. Lee;Wanli Yang;V. Brouet;F. Zhou;W. Ti;J. Xiong;Z. Zhao;T. Sasagawa;T. Kakeshita;H. Eisaki;S. Uchida;A. Fujimori;Z. Hussain;Z. Shen

S.Uchida: "Charge transport in the stripe ordered state of cuprates"Physica C. 388-389. 205-206 (2003)

S.Uchida：“铜酸盐条带有序状态下的电荷传输”Physica C. 388-389。