Structural and electronic properties of two-dimensional hydrogenated Xenes.

Structural and electronic properties of pristine two-dimensional group IV Xenes (X  =  C, Si, Ge, Sn, Pb) and hydrogenated Xenes are studied, using density functional theory (DFT) calculations with and without spin-orbit coupling (SOC). The pristine hexagonal monolayer Xenes show buckled structure upon relaxation except graphene. The buckling [Formula: see text] increases linearly from graphene to plumbene. The band structures without SOC of group-IV Xenes are semi-metallic. However, inclusion of SOC mainly opens the bandgap at the Dirac point. Semi hydrogenation leads to enhanced buckling in all Xenes which indicate a tendency towards more sp