Tip enhanced Raman spectroscopy (TERS) as a probe for the buckling distortion in silicene

Silicene, the all-Si analogue of graphene, is symmetrically buckled in each of the six-membered units and this buckling is periodically translated across the surface. Raman spectra of silicene clusters were calculated using first principles DFT methods to explore the intrinsic buckling in silicene. The presence of metal clusters as a tip over the silicene units affects the intensity of the buckling modes which can be enhanced by increasing the number of atoms in the clusters. The favourable sites of chemisorption of metal clusters over the silicene surface are studied along with the resulting red shift in buckling frequency and chemical enhancement in the Raman intensity.