基于含时密度泛函理论,研究了硅烯量子点的等离激元激发.沿量子点所在的平面方向,体系中有两个主要的等离激元共振带.一个等离激元共振带位于2.0 e V附近,另一个等离激元共振带位于7.0 e V附近.由于离域化的π电子参与了两个等离激元共振带的激发,沿激发方向随着矩形硅烯量子点边长的增加,体系的两个等离激元共振带都发生红移.硅烯量子点的等离激元激发还依赖于边界的构型.此外,由于六角形硅烯量子点的对称性较高,沿量子点所在平面的不同方向激发时,体系的等离激元共振模式相同.
Time-dependent density functional theory has been used to investigate the plasmon excitation processes in silicene quantum dots. Two main plasmon resonance bands were observed running parallel to the direction to the silicene quantum dot plane around 2,0 and 7.0 eV. Given that delocalized rr electrons can participate in the excitation of the two plasmon resonance bands, an increase in the side length of the rectangular silicene quantum dots in the direction of the excitation led to the red-shifting of the two main plasmon resonance bands. Plasmon excitation in silicene quantum dots is also dependent on the edge configuration. Furthermore, because of the relatively high symmetry of the hexagonal silicene quantum dot, the plasmon resonance modes of the quantum dots were found to be identical along the different excitation directions running parallel to the quantum dot plane.