Electronic properties of silicene and multilayer Si films on Ag(111)

Honeycomb structured (4×4) monolayer silicene and   multilayer silicon on Ag(111) have attracted a lot of interest with photoemission studies indicating the presence of π-band Dirac cones near the Fermi level.1,2 In this talk, I will show instead that the π-symmetry states of monolayer silicene lose their local character and the Dirac cones fade out. An interface state of free-electron-like Ag origin accounts for the spectral features that were attributed to silicene π-bands.3,4 For multilayer silicon, the bands previously attributed to π* state with Dirac fermion character are found to derive from the well-known Ag- -Si(111) structure, and from a Si modified Ag(111) interface states.5  

1 P. Vogt et al., Phys. Rev. Lett. 108, 155501 (2012).
2 P. De Padova et al., Appl. Phys. Lett. 102, 163106 (2013), J. Phys.: Condens. Matter 25 382202 (2013).
3 D. Tsoutsou et al., Appl. Phys. Lett. 103, 231604 (2013).
4 S. K. Mahatha et al., Phys. Rev. B 89, 201416(R) (2014). 
5 S. K. Mahatha et al., Accepted in Phys. Rev. B.