Determining the atomic structure of the (4 x 4) silicene layer on Ag(111) by combined grazing-incidence x-ray diffraction measurements and first-principles calculations

摘要

From grazing-incidence x-ray diffraction measurements and density functional theory calculations, we have precisely determined the atomic positions of the Si and Ag atoms forming the (4 x 4) Si/Ag(111) silicene reconstruction. A remarkable agreement is found between the experimental structure factors and the theoretical ones derived from the calculations. Our results confirm the honeycomb structure previously proposed, with a buckling of Si atoms equal to 0.77 angstrom. The Ag substrate atoms are also relaxed, leading to a nonnegligible elastic deformation energy of the substrate, equal to 43 mJ/m(2).