The formation of plasmons through the collective excitation of charge density has generated intense discussions, offering insights into fundamental sciences and potential applications. While the underlying physical principles have been well-established, the effects of many-body interactions and orbital hybridization on plasmonic dynamics remain understudied. In this work, we present the observation of conventional metallic and correlated plasmons in epitaxial La_1–xSr_xNiO₃ (LSNO) films with varying Sr doping concentrations (x = 0, 0.125, 0.25), unveiling their intriguing evolution. Unlike samples at other doping concentrations, the x = 0.125 intermediate doping sample does not exhibit the correlated plasmons despite showing high optical conductivity. Through a comprehensive experimental investigation using spectroscopic ellipsometry and X-ray absorption spectroscopy, the O2p-Ni3d orbital hybridization for LSNO with a doping concentration of x = 0.125 is found to be significantly enhanced, alongside a considerable weakening of its effective correlation U*. These factors account for the absence of correlated plasmons and the high optical conductivity observed in LSNO (0.125). Our results underscore the profound impact of orbital hybridization on the electronic structure and the formation of plasmons in strongly correlated systems. This in turn suggests that LSNO could serve as a promising alternative material in optoelectronic devices.

中文翻译：

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外延钙钛矿镍酸盐中的可调谐集体激发


通过电荷密度的集体激发形成等离子体激元引起了激烈的讨论，为基础科学和潜在应用提供了见解。虽然基本的物理原理已经很明确，但多体相互作用和轨道杂交对等离子体动力学的影响仍有待研究。在这项工作中，我们展示了不同 Sr 掺杂浓度的外延 La _1–x Sr _x NiO ₃ (LSNO) 薄膜中传统金属和相关等离子体激元的观察（ x = 0, 0.125, 0.25)，揭示了它们有趣的演变。与其他掺杂浓度的样品不同，x = 0.125 中间掺杂样品尽管表现出高光导率，但并未表现出相关等离子体激元。通过使用椭圆偏振光谱和X射线吸收光谱的综合实验研究，发现掺杂浓度x = 0.125的LSNO的O2p-Ni3d轨道杂化显着增强，同时其有效相关性U*显着减弱。这些因素解释了在 LSNO (0.125) 中观察到的相关等离子体激元的缺失和高光导率。我们的结果强调了轨道杂化对强相关系统中电子结构和等离子体激元形成的深远影响。这反过来表明LSNO可以作为光电器件中一种有前途的替代材料。