本研究由第一原理出發，以局域化之Wannier函數為基底，描述強束縛激子的波函數。接著利用雙粒子動能核心的構想，透過求解 Bethe-Salpeter Equation (BSE)，得到激子之關聯函數與響應函數，進而可與非彈性光散射實驗比較，以了解強束縛激子的動態傳播特性。我們主要模擬二維單層片狀結構的碳化矽與氮化硼，其強束縛激子的動態行為。此外，由本研究之結果發現，當維度增加時，結構由單層片狀結構，變為雙層片狀結構時，而原本強束縛的激子將不再受限於只能在平面上傳播。 In this thesis ,we perform first-principles calculations to explore the properties strongly bound Frenkel-like excitons. According to the local character ,the wavefunction of Frenkel-like exciton can be represented by the Wannier function in our study. Furthermore ,electronic correlation function and response function can be obtained by solving the Bethe-Salpeter equation with the help of developing two-particle kinetic kernel(T). Our result can be compared with the measurement of inelastic X-ray scattering. Practically ,we focus on the dynamical properties of strongly bound exciton in two-dimensional SiC sheet and BN sheet. Meanwhile ,our results show that exciton could be propagated along the direction perpendicular to the sheet plane by reducing the inter-sheet distance.
