Theory of Strong Coupling Superconductors

强耦合超导体理论

• 批准号: 10640342
• 负责人: YAMADA Kosaku
• 金额: $ 1.86万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640342/
• 关键词: superconductivity; organic conductor; cuprates; Fermi liquid; strong correlation; strong coupling superconductivity; superconducting fluctuation; pseudogap; 異方的超伝導; 強結合理論; ボーズ凝縮; 酸化物超伝導体; 超伝導揺ぎ

One of the most important problems in the high temperature superconductors is the understanding of pseudogap phenomena. We have made clear the origin of the pseudogap by using the T-matrix approximation. The origin is the superconducting fluctuation due to the strong attractive interaction in the quasi-two dimensional system. Through this research we have successfully derived the pseudogap and superconducting gap above and below TィイD2cィエD2, respectively.The other important result obtained by our study is the explanation of origin of the superconductivity in strongly correlated electron systems. By using the perturbation theory we have successfully derived the superconducting state corresponding to each system; the d-wave gap state for the cuprates and the organic superconductor BEDT-TTF and the p-wave gap state for the triplet superconductor SrィイD22ィエD2RuOィイD24ィエD2. These facts show that the origin of superconductivity is the momentum dependence of the interaction originated from the Coulomb repulsion.Especially, theory of superconductivity in SrィイD22ィエD2RuOィイD24ィエD2 is very important. The critical temperature of superconductivity in the system is 1.5K. Even for this low TィイD2cィエD2 we can apply the perturbation theory and predict the appearance of superconductivity including the symmetry. Therefore, we have a powerful method to study the possibility of superconductivity in the strongly correlated systems. This is the most important finding of our study.

高温超导体最重要的问题之一是对赝能隙现象的理解。我们已经通过使用 T 矩阵近似弄清楚了赝能隙的起源。其根源是准二维系统中由于强吸引力相互作用而产生的超导涨落。通过这项研究，我们成功地分别推导了TィイD2cィエD2上方和下方的赝能隙和超导能隙。我们研究获得的另一个重要成果是解释了强相关电子系统中超导性的起源。利用微扰理论我们成功推导了各个系统对应的超导态；铜酸盐和有机超导体BEDT-TTF的d波能隙态以及三线态超导体SriiD22ィエD2RuOiiD24iiD2的p波能隙态。这些事实表明，超导性的起源是源于库仑斥力的相互作用的动量依赖性。特别是SriiD22ィエD2RuOィイD24ィエD2中的超导理论非常重要。系统超导临界温度为1.5K。即使对于这个低 TィイD2cィエD2，我们也可以应用微扰理论并预测超导性的出现，包括对称性。因此，我们有一个强大的方法来研究强相关系统中超导性的可能性。这是我们研究中最重要的发现。

项目成果

T.Jujo,S.Kaikogami,K.Yamada: "Perturbation Theory on the Transition Temperature and Electronic properties of Organic Supperonductors" J.Phys.Soc.Jpn. 68・4. (1999)

T.Jujo、S.Kaikogami、K.Yamada：“有机超导体的转变温度和电子特性的微扰理论”J.Phys.Soc.Jpn 68・4。

S.Koikegonri and K.Yamada: "Strong Coupling Approach of the d-p Model on the Bosis of Fermi Liquid Theory" J.Phys.Soc.Jpn. 67・4. 1114-1117 (1998)

S.Koikegonri 和 K.Yamada：“费米液体理论的 d-p 模型的强耦合方法”J.Phys.Soc.Jpn 67・4（1998）。

S. Fujimoto: "Spin Transport Properties of the Quantum One-Dimensional Non-Linear Siguma Model : an Application to Haldane Gap Systems"J. Phys. Soc. Jpn. 68. 2810-2816 (1999)

S. Fujimoto：“量子一维非线性 Siguma 模型的自旋输运特性：在 Haldane 间隙系统中的应用”J。

M. Mjyazawa, H. Kontani and K. Yamada: "Anomalous Hall Effect in SrィイD22ィエD2RuoィイD24ィエD2"J. Phys. Soc. Jpn. 68. 1625-1631 (1999)

M. Mjyazawa、H. Kontani 和 K. Yamada：“Sr-D22-D2-R-D24-D2 中的异常霍尔效应”J. Phys. 68。1625-1631 (1999)

T. Jujo and K. Yamada: "A Possible Mechanism of the Pseudogap in Organic Superconductor Based on the Superconducting Fluctuation"J. Phys. Soc. Jpn. 68. 2198-2201 (1999)

T. Jujo和K. Yamada：“基于超导涨落的有机超导体中赝能隙的可能机制”J。