  Group V element analogues of graphene have attracted a lot attention recently
due to their semiconducting band structures, which make them promising for next
generation electronic and optoelectronic devices based on two-dimensional
materials. Theoretical investigations predict high electron mobility, large
band gaps, band gap tuning by strain, formation of topological phases, quantum
spin Hall effect at room temperature, and superconductivity amongst others.
Here, we report a successful formation of freestanding like monolayer arsenene
on Ag(111). This was concluded from our experimental atomic and electronic
structure data by comparing to results of our theoretical calculations.
Arsenene forms a buckled honeycomb layer on Ag(111) with a lattice constant of
3.6 {\AA} showing an indirect band gap of about 1.4 eV as deduced from the
position of the Fermi level pinning.
