標題: | ab initio calculated frequency-dependent nonlinear optical properties on CsGeBr3 |
作者: | Tang, L. C. Chang, Y. C. Huang, J. Y. Chang, C. S. 光電工程學系 Department of Photonics |
關鍵字: | first-principles;chi2;frequency-dependent;second-order optical susceptibilities |
公開日期: | 1-一月-2006 |
摘要: | A systematic first-principles calculation of the linear and second-order optical susceptibilities as functions of frequency for CsGeBr3 is presented. Specifically, we study the relation between the structural properties and the optical responses. Three structural deformation factors, Delta alpha, d(Ge), d(X) are used to express the degree of distortion from the ideal perovskite structure in bond angle, Ge position, and anion position, respectively. Based on our first-Principles studies, we find that Delta alpha and d(Ge) increase, while d(X) decreases as we substitute the halo-en ion from Cl to Br and then to I. The dielectric function and the second harmonic generation coefficient are also found to increase with increasing Delta alpha and d(Ge). Our calculation indicates that the direct bandgap, E-g, of CsGeX3 occurs at the R-point for all three compounds, and its magnitude decreases as Delta alpha and d(Ge) increase (i.e. E-g(CsGeI3) < E-g(CsGeBr3) < E-g(CsGeCl3)). Our partial density of states (PDOS) analysis reveals that the valence band maximun (VBM) and conduction band minimum (CBM) are mainly associated with the p-orbitals of Germanium. Interband and intraband analysed results for chi((2))(ijk) in CsGeBr3 can be separated into two main groups of peaks. One was contributed from the magnitude electronic bandgap; the other part was recognized to be attribution from the distortional structural factors. The magnitudes Of chi((2))(ijk) were in the same manner with some reported experiment near the band gap. |
URI: | http://dx.doi.org/10.1117/12.681410 http://hdl.handle.net/11536/146333 |
ISBN: | 0-8194-6373-6 |
ISSN: | 0277-786X |
DOI: | 10.1117/12.681410 |
期刊: | INFRARED AND PHOTOELECTRONIC IMAGERS AND DETECTOR DEVICES II |
Volume: | 6294 |
起始頁: | 0 |
結束頁: | 0 |
顯示於類別: | 會議論文 |