Pressure-induced changes of valence fluctuation in β-YbAlB4 probed by x-ray absorption spectroscopy
Pressure-induced changes of valence fluctuation in β-YbAlB4 probed by x-ray absorption spectroscopy
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X 射线吸收光谱探测压力引起的 β-YbAlB4 价态波动变化
DOI：
10.1103/physrevb.105.155129
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发表时间：
2022
影响因子：
3.7
通讯作者：
Kobayashi Hisao
中科院分区：
文献类型：
--
作者：
Sakaguchi Yui;Ikeda Shugo;Kawamura Naomi;Mizumaki Masaichiro;Kuga Kentaro;Suzuki Shintaro;Sone Keita;Nakatsuji Satoru;Kobayashi Hisao
我们报告了独特的量子临界化合物在压力和低温下的详细价态波动现象。我们直接观察到平均 Yb 价态在约 3 GPa 时压力依赖性的急剧变化，没有压力引起的结构转变。低于 3 GPa，在环境压力下约 55 K 处观察到平均 Yb 价态的温度依赖性异常，对应于先前观察到的近藤相干温度降低，并且该温度在 2.2 GPa 时迅速降至 22 K，与高近藤温度（在环境压力下）的单调下降形成鲜明对比。目前的结果表明，这种降低的近藤相干温度是造成非常规量子临界行为的原因。在 3 GPa 以上，发现平均 Yb 价态的温度依赖性在低温下表现出不连续的变化（分别在 4.8 和 5.5 GPa 下为 10.5 和 9 K）。
We report detailed valence fluctuation phenomena in the unique quantum-critical compoundunder 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 (at ambient pressure). The present results reveal that this reduced Kondo coherence temperature is responsible for the unconventional quantum critical behaviors in. 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).