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.