Distinct Kondo Screening Behaviors in Heavy Fermion Filled Skutterudites with 4f^{1} and 4f^{2} Configurations.
Distinct Kondo Screening Behaviors in Heavy Fermion Filled Skutterudites with 4f^{1} and 4f^{2} Configurations.
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DOI：
10.1103/physrevlett.126.136402
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发表时间：
2021-04
影响因子：
8.6
通讯作者：
X. Lou;T. L. Yu;Y. H. Song-Y. H.-Song-2252290669;C. Wen;W. Z. Wei-W. Z.-Wei-2252303821;A. Leithe-Jasper;Z. F. Ding;L. Shu;S. Kirchner
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文献类型：
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作者：
X. Lou;T. L. Yu;Y. H. Song-Y. H.-Song-2252290669;C. Wen;W. Z. Wei-W. Z.-Wei-2252303821;A. Leithe-Jasper;Z. F. Ding;L. Shu;S. Kirchner
CeOS_{4}Sb_{12}(COS)和ProS_{4}Sb_{12}(POS)是两个具有代表性的化合物，为系统地研究多f电子系统的物理提供了理想的有利条件。具有Ce4f^{1}组态的CoS和具有Pr4f^{2}组态的POS分别表现出明显的近藤绝缘和重费米子超导性质。我们通过角度分辨光电子能谱研究揭示了潜在的微观起源。它们的EV尺度能带结构很好地匹配，代表了ROS_(4)Sb_(12)系统(R=稀土)中传导电子的共同特征。然而，在COS和POS中，f电子与传导电子的相互作用不同。在具有带相关杂化能隙的COS中观察到导电电子和f电子之间的强烈杂化，并直接揭示了近藤绝缘态的发展。虽然POS的基态为单重态，但存在有限但非相干的杂化，这可以用热激发三重态晶体电场的近藤散射来解释。我们的结果有助于我们理解COS和POS中有趣的性质，并清楚地展示了具有4f^{1}和4f^{2}组态的重费米子系统的微观差异。
CeOs_{4}Sb_{12} (COS) and PrOs_{4}Sb_{12} (POS) are two representative compounds that provide the ideal vantage point to systematically study the physics of multi-f-electron systems. COS with Ce 4f^{1}, and POS with Pr 4f^{2} configurations show distinct properties of Kondo insulating and heavy fermion superconductivity, respectively. We unveiled the underlying microscopic origin by angle-resolved photoemission spectroscopy studies. Their eV-scale band structure matches well, representing the common characters of conduction electrons in ROs_{4}Sb_{12} systems (R=rare earth). However, f electrons interact differently with conduction electrons in COS and POS. Strong hybridization between conduction electrons and f electrons is observed in COS with band dependent hybridization gaps, and the development of a Kondo insulating state is directly revealed. Although the ground state of POS is a singlet, finite but incoherent hybridization exists, which can be explained by the Kondo scattering with the thermally excited triplet crystalline electric field state. Our results help us to understand the intriguing properties in COS and POS, and provide a clean demonstration of the microscopic differences in heavy fermion systems with 4f^{1} and 4f^{2} configurations.