The elastic property of quantum critical quasicrystal (QC) Yb₁₅Al₃₄Au₅₁ is analyzed theoretically on the basis of the approximant crystal (AC) Yb₁₄Al₃₅Au₅₁. By constructing the realistic effective model in the AC, we evaluate the 4f-5d Coulomb repulsion at Yb as $U_{fd}\approx 1.46\mathrm{eV}$ realizing the quantum critical point (QCP) of the Yb-valence transition. The RPA analysis of the QCP shows that softening in elastic constants occurs remarkably for bulk modulus and longitudinal mode at low temperatures. Possible relevance of these results to the QC as well as the pressure-tuned AC is discussed.

中文翻译：

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量子临界 Yb-Al-Au 近似晶体和准晶体的弹性软化

量子临界准晶（QC）Yb ₁₅ Al ₃₄ Au ₅₁的弹性特性是在近似晶体（AC）Yb ₁₄ Al ₃₅ Au ₅₁的基础上进行理论分析的。通过在 AC 中构建现实的有效模型，我们将 Yb 处的 4f-5d 库仑斥力评估为${你}_{Fd}\approx 1.46\mathrm{电动汽车}$实现 Yb 价跃迁的量子临界点 (QCP)。QCP 的 RPA 分析表明，在低温下，体积模量和纵向模式的弹性常数软化显着发生。讨论了这些结果与 QC 以及压力调节 AC 的可能相关性。