Fig. 1 Top and side view of the relaxed pristine silicene structure with the atoms used for creating the defects labelled as atom 20 and atom 21
The density of states (DOS) and band structure for pristine silicene is plotted in Fig 2 and shows that pristine silicene is a semi-metallic material as the DOS value at EFermi is zero. The density of states just below and above the Fermi level are mainly contributed to by the π and π∗ orbital. [52]. The valence band can be seen to touch the conduction band just at the symmetry K point which is called the Dirac point. The band gap and the density of states for silicene can be tuned further by the introduction of defects on the silicene structure.