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arXiv 0705.1734cond-mat.str-el
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反铁磁超导体UPd2Al3中f电子局域跃迁的遍历

Itinerant to localized transition of f electrons in antiferromagnetic superconductor UPd2Al3

Shin-ichi Fujimori, Yuji Saitoh, Tetsuo Okane, Atsushi Fujimori, Hiroshi Yamagami, Yoshinori Haga, Etsuji Yamamoto, Yoshichika Onuki

摘要:

固体中的电子通常根据其性质分为类带状巡游电子和类原子局域电子。对于重费米子(HF)的化合物,然而,f电子显示巡回和本地化的行为取决于温度。在特征温度T* 以上,这通常是几K到几十K的数量级,它们的磁性很好地描述了离子f-电子模型,这表明f-电子表现为“本地化”的电子。另一方面,远低于T*,他们的费米面(FS的)已被观察到的磁振荡技术,一般可以很好地解释由“巡回”f-电子模型。这两个模型假设了完全不同的f电子性质,它们如何随温度变化而在定域态和巡游态之间转换,还没有从电子结构的水平上得到理解。本文用角分辨光电子能谱学(ARPES)研究了HF反铁磁超导体UPd_2Al_3在T ~* 以下和T ~* 以上的能带结构,揭示了电子结构与温度的关系。我们已经发现,f带,形成FS的在低温下被排除在FS的在高温下。这些结果从电子结构的角度揭示了同一个f电子如何同时表现出巡游和定域行为,为统一描述HF化合物的定域和巡游性质提供了重要信息.

英文摘要:

Electrons in solids have been conventionally classified as either band-like itinerant ones or atomic-like localized ones depending on their properties. For heavy Fermion (HF) compounds, however, the f electrons show both itinerant and localized behaviours depending on temperature. Above the characteristic temperature T*, which is typically of the order of few K to few tens K, their magnetic properties are well described by the ionic f-electron models, suggesting that the f-electrons behave as 'localized' electrons. On the other hand, well below T*, their Fermi surfaces (FS's) have been observed by magneto-oscillatory techniques, and generally they can be explained well by the 'itinerant' f-electron model. These two models assume totally different natures of felectrons, and how they transform between localized and itinerant state as a function of temperatures has never been understood on the level of their electronic structures. Here we have studied the band structure of the HF antiferromagnetic superconductor UPd2Al3 well below and above T* by angle-resolved photoelectron spectroscopy (ARPES), and revealed the temperature dependence of the electronic structure. We have found that the f-bands, which form the FS's at low temperatures are excluded from FS's at high temperatures. The present results demonstrate how the same f-electrons show both itinerant and localized behaviours on the level of electronic structure, and provide an important information for the unified description of the localized and itinerant nature of HF compounds.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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