Silicene on metal and metallized surfaces: ab initio studies

The deposition of silicene on several metals is investigated. For fcc crystals the (111) surfaces while for hexagonal ones the (0001) surfaces are used. The Ca (111)1 x 1 substrate is found to be the most promising candidate. The silicene adsorption on Ca-functionalized Si(111)1 x 1 and 2 x 1 surfaces is also studied. The 1 x 1 substrates lead to overlayer silicene with hexagonal symmetry and Dirac cones. However, the Dirac points are below the Fermi level, and small energy gaps are opened. In the case of 2 x 1 surfaces, strong lattice relaxation occurs. Only rudiments of conical linear bands remain visible.