In the past decade, two-dimensional (2D) materials have evolved into a big family with emerging new members beyond graphene, such as hexagonal boron nitride (hBN), transition metal dichalcogenides (TMDs), and elemental monolayers (eg silicene, phosphorene). Silicene, the group IV elemental cousin of graphene, has a buckled honeycomb lattice 1 with predicted Dirac band structure 2, 3. It has the potential to be a widely tuneable 2D monolayer, where external fields and surface interactions can ...