论文标题
对二维半导体两光子吸收的激子效应：MOS2和WS2单层的理论和应用
Excitonic effect on two-photon absorption of two-dimensional semiconductors: Theory and applications to MoS2 and WS2 monolayers
论文作者
论文摘要
基于伯特 - 盐方程征素态，我们提出了一种原理多体形式，用于计算半导体的两光子吸收（TPA）系数。我们应用这种形式主义来计算MOS2和WS2单层的TPA光谱。全电子全电力线性化的增强平面波的函数用于求解伯特盐盐方程。计算出的光谱与WS2单层可用实验的光谱非常吻合。与基于独立粒子近似相比，计算出的TPA光谱在与基于独立粒子的近似相比时会显示出显着的激子效应。 MOS2和WS2单层TPA激素过渡的物理起源是通过追踪汇率的过程来揭示的。我们表明，旋转轨道耦合效应会导致特征性的双峰，间隔为半自旋轨道分裂能。这些双峰主要来自K点附近的过渡。
Based on the Bethe-Salpeter equation eigenstates, we present a first-principles many-body formalism for calculating the two-photon absorption (TPA) coefficient of semiconductors. We apply this formalism to calculate the TPA spectra of MoS2 and WS2 monolayers. The all-electron full-potential linearised augmented-plane wave based functions are used for solving the Bethe-Salpeter equation. The calculated spectra are in good agreement with the available experimental ones for WS2 monolayer. The calculated TPA spectra exhibit significant excitonic effects when compared to those based on the independent particle approximation. The physical origin of TPA excitonic transitions of MoS2 and WS2 monolayers are revealed by tracing the sum-over-states process. We show that the spin-orbit coupling effect leads to characteristic double peaks with an interval of half spin-orbit splitting energy. These double peaks mainly originate from the transitions at the vicinity of K point.
