Department of Physics and Astronomy, Vanderbilt University, Nashville, TN-37235, USA.
Department of Physics, Freie University, Berlin, 14195, Germany.
Sci Rep. 2018 Jan 15;8(1):768. doi: 10.1038/s41598-017-18803-y.
We report a combined theoretical/experimental study of dynamic screening of excitons in media with frequency-dependent dielectric functions. We develop an analytical model showing that interparticle interactions in an exciton are screened in the range of frequencies from zero to the characteristic binding energy depending on the symmetries and transition energies of that exciton. The problem of the dynamic screening is then reduced to simply solving the Schrodinger equation with an effectively frequency-independent potential. Quantitative predictions of the model are experimentally verified using a test system: neutral, charged and defect-bound excitons in two-dimensional monolayer WS, screened by metallic, liquid, and semiconducting environments. The screening-induced shifts of the excitonic peaks in photoluminescence spectra are in good agreement with our model.
我们报告了一项关于在具有频率相关介电函数的介质中动态筛选激子的理论/实验综合研究。我们开发了一个分析模型，表明在激子中，粒子间相互作用在从零到特征束缚能的频率范围内被屏蔽，这取决于该激子的对称性和跃迁能量。然后，动态屏蔽问题简化为用有效频率独立的势来简单地求解薛定谔方程。我们使用一个测试系统实验验证了该模型的定量预测：二维单层 WS 中的中性、带电和缺陷束缚激子，由金属、液体和半导体环境屏蔽。光致发光光谱中激子峰的屏蔽诱导位移与我们的模型很好地吻合。
