Lithium tantalate (LiTaO₃) has large technological importance due to numerous applications, especially for motion sensors, radiation detectors, and optical waveguides. In some manufacturing processes temperature treatments are applied to obtain the desired structure or composition. However, the temperature treatment influences the optical and electrical properties of the material due to the incorporation of defects. Unfortunately, the exact nature and concentration of these defects are only insufficiently known. In the present study, temperature-induced defect incorporation in congruent LiTaO₃ crystals under vacuum at 1224 K is investigated. Inelastic neutron spectra are measured in situ to identify the point defects and separate them from further contributions of structural phase transition as well as ferroelectric domain structure. Inelastic neutron scattering data are analysed with respect to small defect concentrations by comparing with density functional theory results. The influence of ferroelectric domains is analysed by Raman and FT-IR spectroscopy. Combining the results of the different techniques, we will elucidate the role of and vacancies during the annealing of congruent LiTaO₃.

中文翻译：

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化学还原全等 LiTaO3 中的缺陷形成：从头算模拟和非弹性中子散射

钽酸锂 (LiTaO ₃ ) 因其众多应用而具有巨大的技术重要性，尤其是用于运动传感器、辐射探测器和光波导。在一些制造过程中，应用温度处理以获得所需的结构或组成。然而，由于缺陷的引入，温度处理会影响材料的光学和电学性能。不幸的是，这些缺陷的确切性质和浓度尚不清楚。在本研究中，研究了在 1224 K 真空下在全等 LiTaO ₃晶体中的温度诱导缺陷掺入。原位测量非弹性中子谱识别点缺陷并将它们与结构相变和铁电畴结构的进一步贡献分开。通过与密度泛函理论结果进行比较，分析了关于小缺陷浓度的非弹性中子散射数据。通过拉曼和 FT-IR 光谱分析铁电畴的影响。结合不同技术的结果，我们将阐明全等 LiTaO ₃退火过程中的作用和空位。