An in-depth analysis of the optical properties of epitaxial (001) oriented LaMnOfilms grown on SrTiOand LaAlOsingle crystal substrates is performed by spectroscopic ellipsometry to determine the complex dielectric function ( = + i) spectra from 0.12 to 5.89 eV. Density Functional Theory and many body perturbation theory within the GW and the Bethe-Salpeter Equation approximations, are also employed to generate theoretical spectra in . Critical point energies (CPs) from 0.91 to 1.49 eV are interpreted as energy separation between and orbitals. CPs from 3.31 to 3.53 eV and 3.75 to 5.23 are interpreted as Mn exchange splitting and strong charge transfer transitions, respectively. Direct and indirect bandgaps from Tauc-plots are identified in the range of 0.100–0.594 eV. Anisotropy presents in LaMnO on LaAlO is attributed to substantial distortion in the out-of-plane epitaxial strain compared to LaMnO on SrTiO. These findings provide a comprehensive understanding of the origins and characteristics of features observed in optical properties of epitaxial LaMnO, offering insights for development of optical and electronic applications based on these materials.

中文翻译：

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外延 LaMnO3 薄膜复杂光学特性和光学跃迁的解释


通过光谱椭圆光度法对在 SrTiO 和 LaAlO 单晶基底上生长的外延 (001) 取向 LaMnO 薄膜的光学特性进行了深入分析，以确定 0.12 至 5.89 eV 的复杂介电函数 ( = + i) 光谱。密度泛函理论和 GW 内的许多体微扰理论以及 Bethe-Salpeter 方程近似也可用于生成 中的理论谱。 0.91 至 1.49 eV 的临界点能量 (CP) 被解释为 和 轨道之间的能量分离。 3.31 至 3.53 eV 和 3.75 至 5.23 的 CP 分别被解释为 Mn 交换分裂和强电荷转移跃迁。 Tauc 图的直接和间接带隙确定在 0.100–0.594 eV 范围内。与 SrTiO 上的 LaMnO 相比，LaAlO 上的 LaMnO 中存在的各向异性归因于面外外延应变的显着变形。这些发现提供了对外延LaMnO光学性质中观察到的特征的起源和特征的全面了解，为基于这些材料的光学和电子应用的开发提供了见解。