Abstract
We study the electronic structure of Tsai-type cluster-based quasicrystalline approximants, Au64Ge22Yb14 (AGY-I), Au63.5Ge20.5Yb16 (AGY-II), and Zn85.4Yb14.6 (Zn-Yb), by means of photoemission spectroscopy. In the valence band hard x-ray photoemission spectra of AGY-II and Zn-Yb, we separately observe a fully occupied Yb 4f state and a valence fluctuation derived Kondo resonance peak, reflecting two inequivalent Yb sites, a single Yb atom in the cluster center and its surrounding Yb icosahedron, respectively. The fully occupied 4f signal is absent in AGY-I containing no Yb atom in the cluster center. The results provide direct evidence for a heterogeneous valence state in AGY-II and Zn-Yb.
Original language | English |
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Article number | 241102 |
Journal | Physical Review B |
Volume | 96 |
Issue number | 24 |
DOIs | |
Publication status | Published - 2017 Dec 11 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics