Here we have investigated the role of electron phonon coupling on the Raman spectrum of narrow bandgap semiconductors APd3O4 (A = Ca, Sr) and hole-doped system Sr0.85Li0.15Pd3O4. Four Raman active phonons are observed at room temperature for all three compounds as predicted by factor group analysis. The lowest energy phonon (~190/202 cm-1) associated with Pd vibrations is observed to exhibit an asymmetric Fano-like lineshape in all the three compounds, indicating the presence of an interaction between the phonon and the electronic continuum. The origin of the electronic continuum states and electron-phonon coupling are discussed based on our laser power- and temperature-dependent Raman results. We have observed an enhanced strength of electron-phonon coupling in Sr0.85Li0.15Pd3O4 at low temperatures which can be attributed to the metallicity in this doped compound.

中文翻译：

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APd3O4 中的电子-声子耦合：A = Ca、Sr 和 Sr0.85Li0.15

在这里，我们研究了电子声子耦合对窄带隙半导体 APd3O4 (A = Ca, Sr) 和空穴掺杂系统 Sr0.85Li0.15Pd3O4 的拉曼光谱的作用。正如因子组分析所预测的那样，在室温下对所有三种化合物都观察到了四个拉曼活性声子。观察到与 Pd 振动相关的最低能量声子 (~190/202 cm-1) 在所有三种化合物中都表现出不对称的类 Fano 线形，表明声子和电子连续体之间存在相互作用。基于我们的激光功率和温度相关的拉曼结果讨论了电子连续态和电子 - 声子耦合的起源。我们观察到 Sr0.85Li0 中电子 - 声子耦合的强度增强。