Abstract
J.Phys.: Condens. Matter, 25, 225301 (2013) In this Letter, we present the first non-contact atomic force microscopy
(nc-AFM) of a silicene on silver (Ag) surface, obtained by combining
non-contact atomic force microscopy (nc-AFM) and scanning tunneling microscopy
(STM). STM images over large areas of silicene grown on Ag(111) surface show
both (sqrt13xsqrt13)R13.9{\deg} and (4x4) superstructures. For the widely
observed (4x4) structure, the nc-AFM topography shows an atomic-scale contrast
inversion as the tip-surface distance is decreased. At the shortest tip-surface
distance, the nc-AFM topography is very similar to the STM one. The observed
structure in the nc-AFM topography is compatible with only one out of two
silicon atoms being visible. This indicates unambiguously a strong buckling of
the silicene honeycomb layer.