论文标题
$β$ -ligao $ _2 $的带隙重归其化和光学特性的第一原理研究
First-principles study of the bandgap renormalization and optical property of $β$-LiGaO$_2$
论文作者
论文摘要
$β$ -ligao $ _2 $带有原晶型沃尔兹特衍生的结构是候选超速直接带式袋式半导体。在这项工作中，使用非绝热的Allen-Heine-Cardona方法，我们研究了由电子波耦合产生的带隙重新归一化。我们发现以$γ$为主的差距为-0.362 eV的零点运动校正相当大，这是由长波长纵向光学声子的贡献所主导的。 $β$ -ligao $ _2 $的带隙随温度升高而单调降低。我们通过将模型的贝碱方程方法与独立粒子近似的模型进行比较来研究光谱。与实验的定性一致性，计算出的光谱包括电子孔相互作用表现出强烈的激发效应。分析了带有带的跨段过渡和激子状态的结合能。
$β$-LiGaO$_2$ with an orthorhombic wurtzite-derived structure is a candidate ultrawide direct-bandgap semiconductor. In this work, using the non-adiabatic Allen-Heine-Cardona approach, we investigate the bandgap renormalization arising from electron-phonon coupling. We find a sizable zero-point motion correction of -0.362 eV to the gap at $Γ$, which is dominated by the contributions of long-wavelength longitudinal optical phonons. The bandgap of $β$-LiGaO$_2$ decreases monotonically with increasing temperature. We investigate the optical spectra by comparing the model Bethe-Salpether equation method with the independent-particle approximation. The calculated optical spectra including electron-hole interactions exhibit strong excitonic effects, in qualitative agreement with experiment. The contributing interband transitions and the binding energy for the excitonic states are analyzed.
