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Electronic structure and isomer shift of valence-fluctuating β-YbAIB4

The 5th Joint International Conference on Hyperfine Interactions and Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2014)

Hisazumi Akai

概要/Abstract

Layered Yb based heavy fermion material β-YbAlB4 is known to be quantum critical and superconducting at Tc=80mK without any doping.
So far there has been no other known pure system showing quantum criticality at ambient pressure, namely, the system is on a quantum critical point at stoichiometry and zero pressure.
Furthermore the hard x-ray photoemission spectroscopy (HX-PES) proved that the valence of +2.75 for Yb, meaning that the system was in mixed valent; very rare case that valence-fluctuating system also shows a quantum criticality.
It is therefore crucial to study the correlation between the valence number of Yb and the elecronic structure of the system.
One of the possible ways to study the valence of Yb may be a measurement of the Mossbauer isomer shift of Yb.
This should be possible with the nuculear resonance forward scattering (NRSF) using synchrotron radiation.
Unfortunately there has been no report of NRSF measurements on Yb systems.
However, to make a theoretical prediction prior to such experiments will provide us with some pieces of information that may facilitate the effort revealing the nature of this novel quantum critical system.



研究活動

元素戦略拠点

触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
高効率モーター用磁性材料技術研究組合
高効率モーター用 磁性材料技術研究組合