Plasmon excitation in hydrogenated silicene nanostructures

Abstract

The impacts of the hydrogenation method and hydrogenation concentration on the plasmon excitations in hydrogenated silicene nanostructures are studied by the time-dependent density functional theory. Chair and Z-line conformations of the hydrogenated silicene nanostructure are mainly considered. When the whole silicene nanostructure is hydrogenated, because the delocalized π electrons form sp3 hybrid orbitals, the low energy plasmon resonance mode disappears. Compared with the hydrogenation that occurred in the middle area of nanostructure, when the hydrogenation occurred in the boundary area, the resonance intensity of the low-energy plasmon decreases greatly. In the high energy region, hydrogenation methods have important effects on plasmon excitation. For the chair-conformation hydrogenated silicene nanostructure, compared with pure silicene nanostructures, the band of high energy plasmon resonance spreads toward the low energy end. However, for the Z-line conformation hydrogenated silicene nanostructure, both the resonance band and the main absorption peak of the high energy plasmon have a blue shift. Moreover, the shape of the resonance band of high energy plasmon is different for hydrogenated silicene nanostructures of different conformations.