Dynamics of valence fluctuation in quantum criticalities for Yb valence fluctuation compounds

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05182
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: University of Hyogo
• Principal Investigator: Kobayashi Hisao 兵庫県立大学, 物質理学研究科, 教授 (40250675)
• Co-Investigator(Kenkyū-buntansha): 池田 修悟 兵庫県立大学, 物質理学研究科, 助教 (80414580)
• Co-Investigator(Renkei-kenkyūsha): NAKATSUJI Satoru 東京大学, 物性研究所, 教授 (70362431)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: メスバウー分光 / 価数揺動 / 量子臨界性 / 電荷揺らぎダイナミックス

Outline of Final Research Achievements

The synchrotron-radiation based 174Yb Mossbauer spectroscopy is a state-of-the-art technique to investigate the Yb electronic states in materials. We have carried out the first measurement under multi-extreme conditions in the world. The 174Yb ossbauer spectra of b-YbAlB4 observed at lower temperature than 5 K are revealed that the valence fluctuation time is slower than 1 ns. Furthermore, our measurements of 174Yb Mossbauer spectra for b-YbAlB4 under high-pressure at 2K indicate that this slower valence fluctuation in b-YbAlB4 is suppressed at about 2 GPa by external pressure. These results make it clear that the slower valence fluctuation in b-YbAlB4 at a lower temperature and ambient pressure corresponds to the anomalous quantum criticalities. This is a first clear experimental evidence of the relation between quantum criticalities and valence fluctuations.

Free Research Field

凝縮系物理