2010年6月
Strong Valence Fluctuation in the Quantum Critical Heavy Fermion Superconductor beta-YbAlB4: A Hard X-Ray Photoemission Study
PHYSICAL REVIEW LETTERS
- 巻
- 104
- 号
- 24
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1103/PhysRevLett.104.247201
- 出版者・発行元
- AMER PHYSICAL SOC
Electronic structures of the quantum critical superconductor beta-YbAlB4 and its polymorph alpha-YbAlB4 are investigated by using bulk-sensitive hard x-ray photoemission spectroscopy. From the Yb 3d core level spectra, the values of the Yb valence are estimated to be similar to 2.73 and similar to 2.75 for alpha- and beta-YbAlB4, respectively, thus providing clear evidence for valence fluctuations. The valence band spectra of these compounds also show Yb2+ peaks at the Fermi level. These observations establish an unambiguous case of a strong mixed valence at quantum criticality for the first time among heavy fermion systems, calling for a novel scheme for a quantum critical model beyond the conventional Doniach picture in beta-YbAlB4.
- リンク情報
- ID情報
-
- DOI : 10.1103/PhysRevLett.104.247201
- ISSN : 0031-9007
- Web of Science ID : WOS:000278734800001