铌酸锂与钽酸锂材料体系中光学带隙的温度依赖性
On the temperature dependence of the optical band gap in the material system of lithium niobate and lithium tantalate
AI总结：
研究铌酸锂与钽酸锂的光学带隙温度依赖性，揭示其带隙差异源于电子-声子耦合与声子能量，开发PhoQS-Treat软件，推动铌酸锂基器件发展
AI中文摘要：
铌酸锂与钽酸锂广泛应用于光学和电子领域，且在低温应用中的使用日益增多。尽管它们应用广泛，但作为温度函数的光学带隙及其与晶体化学计量比的关联尚未得到充分表征。本研究通过光学透射光谱法，在7K至1000K的温度范围内，研究了同成分、化学计量比、掺MgO及掺Er的铌酸锂，以及同成分钽酸锂的光吸收特性。结果表明，室温下不同化学计量比之间观察到的光学带隙差异，主要并非源于本征电子结构，而是源于不同的电子-声子耦合及平均声子能量。此外，由于对光学活性掺杂剂的关注度提升，我们以掺Er铌酸锂中523nm吸收线的温度偏移为例进行了研究。为便于后续分析，我们提供了开源软件套件PhoQS-Treat（Tauc回归边缘分析工具），该工具可实现自动Tauc回归及其他分析功能。本研究推动了高性能铌酸锂基器件的发展。
英文摘要：
Lithium niobate and lithium tantalate see widespread use in optics and electronics, and are increasingly used for cryogenic applications. Despite their broad deployment, their optical band gap and its relation to the crystal stoichiometry are not well characterised as a function of temperature. In this work, we study the optical absorption properties of congruent, stoichiometric, MgO-doped and Er-doped lithium niobate as well as congruent lithium tantalate across the temperature range between 7~K and 1000~K by means of optical transmission spectroscopy. Our results demonstrate that the difference of the optical band gap typically observed at room temperature between different stoichiometries is not primarily attributable to the intrinsic electronic structure, but rather to different electron-phonon couplings and the average phonon energies. Additionally, we exemplarily study the temperature shift of the 523 nm absorption line in Er-doped lithium niobate due to the increased interest in optically active dopants. To facilitate future analyses, we present the open-source software suite PhoQS-Treat (Tauc Regression Edge Analysis Tool), which enables automated Tauc regressions alongside additional analytical capabilities. This work advances the development of high-performance lithium niobate-based devices.
