Strong valence fluctuation in the quantum critical heavy fermion superconductor β-YbAlB4: A hard x-ray photoemission study

M. Okawa, M. Matsunami, K. Ishizaka, R. Eguchi, M. Taguchi, A. Chainani, Y. Takata, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, K. Kuga, N. Horie, S. Nakatsuji, S. Shin

研究成果: Article同行評審

80 引文 斯高帕斯(Scopus)

摘要

Electronic structures of the quantum critical superconductor β-YbAlB4 and its polymorph α-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 ∼2.73 and ∼2.75 for α- and β-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 β-YbAlB4.

原文English
文章編號247201
期刊Physical review letters
104
發行號24
DOIs
出版狀態Published - 2010 六月 14

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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