论文标题
强烈的电子 - 音波耦合和增强的声子Grüneisen参数在价触发金属eupd $ _2 $ si $ _2 $
Strong electron-phonon coupling and enhanced phonon Grüneisen parameters in valence-fluctuating metal EuPd$_2$Si$_2$
论文作者
论文摘要
我们研究了通过极化分辨的拉曼光谱法研究EUPD $ _2 $ si $ _2 $的价值交叉和强元偶联。完全对称的声子模式在低温下显示出强烈的不对称线形，表明该模式与电子孔刺激连续体之间的Fano型相互作用。此外，声子模式的频率和线宽在整个价值的温度上表现出异常，表明价波动与晶格振动之间的耦合。特别是，两个声子模式显示出显着增强的格涅森参数，表明靠近临界弹性状态。结构变化和价变化对声子异常的相对贡献通过密度功能理论计算评估。
We study the valence crossover and strong electron-phonon coupling of EuPd$_2$Si$_2$ by polarization-resolved Raman spectroscopy. The fully-symmetric phonon mode shows strongly asymmetric lineshape at low temperature, indicating Fano-type interaction between this mode and a continuum of electron-hole excitations. Moreover, the frequency and linewidth of the phonon modes exhibit anomalies across the valence-crossover temperature, suggesting the coupling between valence fluctuations and lattice vibration. In particular, two phonon modes show significantly enhanced Grüneisen parameter, suggesting proximity to a critical elasticity regime. The relative contribution of the structural change and valence change to the phonon anomalies is evaluated by density functional theory calculations.
