Study of the Instability of the Fermi Surface and the Heavy Fermion State around the Quantum Phase Transition for the Pressure-Induced Superconductor

压感超导体量子相变费米面和重费米子态不稳定性研究

• 批准号: 14540337
• 负责人: SETTAI Rikio
• 金额: $ 1.92万
• 依托单位: Osaka Unioversity
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540337/
• 关键词: dHvA effect; Pressure; Heavy Fermion; Pressure-induced Superconductor; Strongly Correlated Electron System; Fermi Surface; Rare Earth Compounds; 量子相転移; 超伝導; CeIn3; CeRhIn5; ドハースファン・アルフェン効果

The character of the 4f-electron in cerium compounds plays an important role on magnetic and charge orderings, spin and valence fluctuations, heavy fermions and anisotropic superconductivity. The de Haas-van Alphen (dHvA) experiment is a powerful tool to study the Fermi surface properties for the 4f-electron systems. For example, the localized 4f-electron character was confirmed in CeB_6,CeIn_3 and CeRhIn_5. On the other hand, the itinerant 4f-electron character was clarified in CeSn_3,CeRu_2Si_2 and CeCoIn_5.In order to clarify the charter of the 4f-electron around the quantum critical point where the magnetic ordering state of an antiferromagnet changes to the paramagnetic one by applying pressure. We have developed the pressure cell for the dHvA experiment under pressure up to 3 GPa. We have studied the change of the Fermi surface properties in antifermmagnets CeRh_2Si_2,CeRhIn_5,CeIn_3 and CePt_3Si.We found the abrupt change of the Fermi surface at the critical pressure P_c in CeRh_2Si_2,CeRhIn_5 and CeIn_3. The change of the Fermi surface indicates that the 4f-electron character is changed from localized to itinerant. Namely, the 4f electron above P_c contributes to the volume of the Fermi surface as the conduction electron. Interestingly, the pressure-induced heavy fermion state with large effective mass was observed around P_c, where the pressure-induced superconductivity appears. We also carried out the dHvA experiments under pressure in CePt_3Si without inversion symmetry in the crystal structure. Although the overall Fermi surface was not observed in CePt_3Si, a new branch with relatively large effective mass was observed above P_c, indicating the change of the electronic state.

铈化合物中4f电子的性质对磁有序、电荷有序、自旋涨落、价涨落、重费米子和各向异性超导电性都有重要的影响。de Haas-van Alphen（dHvA）实验是研究4f电子系统费米面性质的有力工具。例如，在CeB_6，CeIn_3和CeRhIn_5中证实了4f电子的局域化特征。另一方面，在CeSn_3，CeRu_2Si_2和CeCoIn_5中发现了巡游4f电子的特征。为了阐明反铁磁体在压力作用下从磁有序态转变为顺磁有序态的量子临界点附近4f电子的特征。我们已经开发出的dHvA实验压力下的压力单元高达3 GPa。研究了反铁磁体CeRh_2Si_2，CeRhIn_5，CeIn_3和CePt_3Si中费米面性质的变化，发现在临界压力Pc处，CeRh_2Si_2，CeRhIn_5，CeIn_3的费米面性质发生突变。费米面的变化表明4f电子的性质由定域性变为巡游性。有趣的是，在P_c附近观察到了具有大有效质量的压力诱导重费米子态，在那里出现了压力诱导超导电性。我们还在没有反转对称性的CePt_3Si中进行了加压下的dHvA实验。在CePt_3Si中，虽然没有观察到完整的费米面，但在P_c以上观察到一个新的具有相对较大有效质量的分支，表明电子态发生了变化。

项目成果

De Haas-Van Alphen experiments under extreme conditions of low temperature, high field and high pressure, for high-quality cerium and uranium compounds.

De Haas-Van Alphen 在低温、高场和高压的极端条件下进行实验，以获得高质量的铈和铀化合物。

• 发表时间: 2003
• 期刊: J.Magn.Magn.Mater. 262
• 作者: H.Shishido et al.;R.Settai et al.;H.Shishido;R.Settai et al.;R.Settai et al.;H.Shishido et al.;R.Settai et al.;M.Nakashima;Y.Onuki et al.;T.Yasuda et al.;M.Nakashima et al.;Y.Onuki et al.;T.Ueda et al.;T.Yasuda et al.;R.Settai et al.;Y.Onuki et al.;T.Yasuda et al.;S.Hashimoto et al.;M.Nakashima et al.;R.Settai et al.;S.Araki et al.;Settai et al.;Y.Onuki et al.;M.Nakashima et al.;H.Shishido et al.;R.Asai et al.;M.Nakashima;M.Nakashima et al.;M.Nakashima et al.;H.Shishido et al.;S.Kirita et al.;R.Settai et al.;H.Shishido et al.;R.Settai et al.
• 通讯作者: R.Settai et al.

R.Settai et al.: "De Haas-van Alphen Effect under pressure in UGe2"Journal of Nuclear Science and Technology. supp.3. 94-97 (2002)

R.Settai 等人：“UGe2 压力下的德哈斯-范阿尔芬效应”核科学与技术杂志。

A Change of the Fermi Surface in CeIn_3 Under Pressure

CeIn_3在压力下费米面的变化

• 发表时间: 2004
• 期刊: J.Magn.Magn.Mat. 272-276
• 作者: R.Settai

De Haas-van Alphen Experiments Under Pressure in UGe_2

UGe_2 压力下的德哈斯-范阿尔芬实验

• 发表时间: 2003
• 期刊: Acta Physica Polonica B 34
• 作者: Shiobara;H.;R.Settai et al.
• 通讯作者: R.Settai et al.

de Haas van Alphen effect of CeRhIn_5 and CeCoIn_5 under pressure

CeRhIn_5 和 CeCoIn_5 在压力下的德哈斯范阿尔芬效应

• 发表时间: 2004
• 期刊: Journal of Magnetism and Magnetic Materials 272-276
• 作者: 増本康平;山田冨美雄;Hiroaki Shishido et al.;Hiroaki Shishido et al.;Hiroaki Shishido et al.
• 通讯作者: Hiroaki Shishido et al.