Letter abstract

Nature Physics 3, 618 - 622 (2007)
Published online: 1 July 2007 | doi:10.1038/nphys651

Subject Categories: Condensed-matter physics | Materials physics

Itinerant to localized transition of f electrons in the antiferromagnetic superconductor UPd2Al3

Shin-Ichi Fujimori1, Yuji Saitoh1, Tetsuo Okane1, Atsushi Fujimori1,2, Hiroshi Yamagami1,3, Yoshinori Haga4, Etsuji Yamamoto4 & Yoshichika O macrnuki4,5


In heavy-fermion compounds, f electrons show both itinerant and localized behaviour depending on the temperature1. Above a characteristic temperature, T*, their magnetic properties can be described by completely 'localized' f-electron models. On the other hand, well below T*, their Fermi surfaces can be explained by the 'itinerant' f-electron model2. These two models assume totally different natures of the f electrons, and how they transform between these states as a function of temperature has never been understood at the level of their electronic structures. Here, we use angle-resolved photoelectron spectroscopy to study the band structure of the heavy-fermion antiferromagnetic superconductor UPd2Al3 below and above T*, and find that the f bands, which form the Fermi surfaces at low temperatures, are excluded from the Fermi surfaces at high temperatures. This result demonstrates how the same f electrons can be both itinerant and localized.

  1. Synchrotron Radiation Research Unit, Japan Atomic Energy Agency, Sayo, Hyogo 679-5148, Japan
  2. Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
  3. Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555, Japan
  4. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
  5. Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan

Correspondence to: Shin-Ichi Fujimori1 e-mail: fujimori@spring8.or.jp

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