Wide quantum critical region of valence fluctuations: Origin of robust quantum criticality in quasicrystal Yb15Al34Au51 under pressure

International Conference on Strongly Correlated Electron Systems 2014

Watanabe, Shinji^1 ; Miyake, Kazumasa^2

Department of Basic Sciences, Kyushu Institute of Technology, Kitakyushu, Japan^1

Toyota Physical and Chemical Research Institute, Nagakute, Japan^2

关键词: Concentric shells;    Ground state phase diagram;    Quantum critical;    Quantum critical points;    Quantum criticality;    T-P phase diagram;    Valence fluctuations;    Valence transitions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012087/pdf
DOI  :  10.1088/1742-6596/592/1/012087

来源: IOP

【 摘 要 】

The mechanism of the emergence of robust quantum criticality in the heavy- electron quasicrystal YR15Al34Au51is analyzed theoretically. By constructing a minimal model for the quasicrystal and its crystalline approximant, which contain concentric shell structures with Yb and Al-Au clusters, we show that a set of quantum critical points of the first-order valence transition of Yb appears as spots in the ground-state phase diagram. Their critical regions overlap each other, giving rise to a wide quantum critical region. This well explains the robust criticality observed in YR15Al34Au51under pressure, and predicts the emergence of the common criticality in the crystalline approximant under pressure. The wider critical region in the quasicrystal than that in the crystalline approximant in the T-P phase diagram and the field-induced valence-crossover «region» in the T-H phase diagram are predicted to appear.