Atomic arrangement of Si adatom on the Silicene/Ag(111) surface

Abstract

Silicene is a two-dimensional material with a honeycomb structure of silicon atoms that exhibits exotic electronic properties. Exploring Si adatom on monolayer silicene opens up new possibilities for studying tunable all-silicon-based devices at an atomic scale. Here we use non-contact atomic force microscopy and scanning tunneling microscopy to visualize and control the Si adatom on monolayer silicene at atomic resolution. We demonstrate that Si adatom forms a two-dimensional island on monolayer silicene. Si adatom can be manipulated on monolayer silicene, thereby delivering a tunable low-dimensional Si structure at an atomic scale. Local reconstruction of monolayer silicene with Si adatom has been confirmed by density functional theory calculations. Our results suggest that controlling the buckling structure of monolayer silicene by positioning Si adatom will locally tune the band structures and functionalities of monolayer silicene which is important for applications.