Site web ESPCI
Jeudi 5 Septembre 2013, 14h
Amphi Holweck, Esc C, 1ème etage
Silicene : experimental evidence and properties of the graphene-like form of silicon
Antoine Fleurence
School of Materials Science, Japan Advanced Institute of Science and Technology
1-1 Asahidai, Ishikawa 923-1292, Japan
Silicene, the graphene-like allotrope of silicon is the object of a recently raised enthusiasm, due to the perspectives opened by the novelty of its electronic, physical and chemical properties. Although the structure of silicene deviates from that of planar graphene by the buckling of the honeycomb structure, it also possesses a π electronic system which, in the hypothetical free-standing form, gives rise to Dirac cones.
So far, silicene only exists in epitaxial forms on metallic substrates. It can be grown either by depositing silicon atoms on substrates like Ag(111) or Ag(110) or, as we demonstrated, by the spontaneous segregation of silicon on the (0001) surface of zirconium diboride (ZrB2) thin films grown on Si(111).
As the so-obtained atom-thick sheet is uniform over a large area, it is a perfect template for the study of the properties of silicene. The multi-techniques investigation we carried out pointed out the intimate relation between the internal structure of silicene and its electronic properties. In particular it shows that the deviation of the honeycomb structure from that of free-standing silicene, allowed by the larger degree of flexibility of the internal structure with respect to that of graphene, is able to open a suitable gap in the Dirac cones.