Pressure-induced changes of valence fluctuation in β - YbAlB 4 probed by x-ray absorption spectroscopy
- University of Hyogo, Koto (Japan); OSTI
- University of Hyogo, Koto (Japan)
- Japan Synchrotron Radiation Research Institute, Hyogo (Japan)
- University of Tokyo (Japan)
- University of Tokyo (Japan); Johns Hopkins University, Baltimore, MD (United States)
Here we report detailed valence fluctuation phenomena in the unique quantum-critical compound β-YbAlB4 under pressures and at low temperatures. We directly observed the drastic change in the pressure dependence of the mean Yb valence at about 3 GPa with no pressure-induced structural transition. Below 3 GPa, the anomaly in the temperature dependences of the mean Yb valence was observed at about 55 K under ambient pressure, corresponding to a previously observed reduced Kondo coherence temperature, and this temperature rapidly decreases to 22 K at 2.2 GPa, in contrast to the monotonous decrease of the high Kondo temperature (~250K at ambient pressure). The present results reveal that this reduced Kondo coherence temperature is responsible for the unconventional quantum critical behaviors in β-YbAlB4. Above 3 GPa, it was found that the temperature dependence of the mean Yb valence exhibits a discontinuous change at low temperature (10.5 and 9 K under 4.8 and 5.5 GPa, respectively).
- Research Organization:
- Johns Hopkins University, Baltimore, MD (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Japan Society for the Promotion of Science (JSPS)
- Grant/Contract Number:
- SC0019331
- OSTI ID:
- 1979745
- Journal Information:
- Physical Review. B, Journal Name: Physical Review. B Journal Issue: 15 Vol. 105; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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