SOLID STATE PROPERTY OF HIGHLY CORRELATED CONDUCTING SYSTEMS

高度相关传导系统的固态特性

• 批准号: 06244103
• 负责人: ONUKI Yoshichika
• 金额: $ 210.69万
• 依托单位: OSAKA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06244103/
• 关键词: Highly Correlated Conducting Systems; Heavy Electron; Anisotropic Superconductivity; Quadrupolar Ordering; Kondo Insulator; Non-Ferm Liquid; Metamagnetism; de Haas-van Alphen Effect; ドハース・ファンアルフェン効果; 強相関電子系; ギャップ近藤; 希土類化合物; ウラン化合物; ギャップ近藤状態 /

We have made big progress in anisotropic superconductivity of the heavy electron systems . When we compare the phonon-mediated attractive interaction to the strong repulsive interaction among the quasiparticles with an f-electron character, it is theoretically difficult for the former to overcome the latter one. To avoid a large overlap of the wave functions of the paired particles, the heavy electron system would rather choose an anisotropic channel, like a p-wave spin triplet or a d-wave spin singlet state, to form Cooper pairs. We have continued in studying non-BCS superconductivity of uranium compounds, and have clarified spin-triplet (p-or f-wave) superconductivity in UPtィイD23ィエD2 from the NMR-Knight shift experiment and also observed a magnetic exci-tation gap associated with d-wave superconductivity of UPdィイD22ィエD2AlィイD23ィエD2.We have observed the de Haas-van Alphen oscillation in the normal and superconducting mixed states of CeRuィイD22ィエD2 and URuィイD22ィエD2SiィイD22ィエD2. The qusiparticle scattering in the mixed state is discussed on the basis of the Maki theory.Another progress has been also made in quadrupolar compounds. Antiferroquadrupolar ordering of CeBィイD26ィエD2, where the experimental analyses were inconsistent, is clarified theoretically by considering dipole, quadrupole and octupole in magnetic fields. The metamagnetic transition of PrCuィイD22ィエD2 brings about an interchange between the easy and hard axes' directions of the magnetization. This interesting phenomenon is explained on the basis of the quadrupolar interaction. Furthermore, precise experiments have been done for antiferroquadrupolar com-pounds of PrPbィイD23ィエD2, TmTe and CeィイD23ィエD2PdィイD220ィエD2GeィイD26ィエD2.In addition to these experiments, many experimental results have been obtained for metamagnetism of heavy electron systems, Kondo insulators and non-Fermi liquid effect.

我们在重电子系统的各向异性超导电性方面取得了很大的进展。当我们比较声子介导的吸引相互作用和具有f-电子特征的准粒子之间的强排斥相互作用时，理论上前者很难克服后者。为了避免成对粒子的波函数有很大的重叠，重电子系统宁愿选择一个各向异性的通道，比如p波自旋三重态或d波自旋单重态，以形成库珀对。我们继续研究铀化合物的非BCS超导性，并澄清了自旋三重态利用核磁共振-奈特位移实验研究了UPt超晶格D23超晶格D2的p波或f波超导性，并观察到与UPd超晶格D22超晶格D2 Al超晶格D23超晶格D2的d波超导性有关的磁激发能隙。CeRu_（22）Si_（22）O_（本文在Maki理论的基础上讨论了混合态准粒子散射，并在四极化合物中取得了新的进展。通过考虑磁场中的偶极、四极和八极，从理论上澄清了CeB_2D_26的反铁四极有序，实验分析与此不一致. PrCu_（22）Cu_（22）Cu_（22）D_2的变磁转变导致易磁化轴和难磁化轴方向的互换。这一有趣的现象是解释的基础上的四极相互作用。此外，还对反铁四极化合物PrPb_（23）Pd_（23）D_2、TmTe和Ce_（23）Pd_（22）Ge_（26）Pd_（22）D_2进行了精确的实验研究。此外，还对重电子系统的变磁性、近藤绝缘体和非费米液体效应进行了大量的实验研究。