arXiv subjects

Y. Colignon

Publications and source records attributed to Y. Colignon.

2 recordsLinked to original sources

arXiv2014

A comprehensive study of the (2R3x2R3)R30 structure of silicene on Ag(111)

The deposition of one silicon monolayer on Ag(111) gives rise to a set of superstructures depending on growth conditions. These superstructures are correlated to the epitaxy between the honeycomb structure of silicon (so called silicene) and the silver substrate. In this paper, from a detailed re-analysis of experimental results, obtained by Scanning Tunneling Microscopy and by Low Energy Electron Diffraction on the (2R3x2R3)R30 structure, we propose a new atomic model of the silicene layer based on periodic arrangements of perfect areas of (2R3x2R3)R30 surrounded by defect areas. A generalization of this model explains the main experimental observations: deviation of the average direction, Moire patterns and apparent global disorder. In the frame of the proposed model, the apparent disorders observed on the STM images, would be topological effects, i.e. the silicene would keep a quasi-perfect honeycomb structure.

cond-mat.mtrl-sci↗

arXiv2012

Growth of silicene layers on Ag(111): unexpected effect of the substrate temperature

The deposition of one silicon monolayer on the silver (111) substrate in the temperature range 150-300$^\circ$C, gives rise to a mix of (4$\times$4), ($2\sqrt{3}\times 2\sqrt{3}$)R30$^\circ$ and ($\sqrt{13}\times\sqrt{13}$)R13.9$^\circ$ superstructures which strongly depends on the substrate temperature. We deduced from a detailed analysis of the LEED patterns and the STM images that all these superstructures are given by a quasi identical silicon single layer with a honeycomb structure (i.e. a silicene-like layer) with different rotations relatively to the silver substrate. The STM images morphology are explained from the relative position of the silicon atoms relative to the silver atoms. A complete analysis of all possible rotations of the silicene layer predicts also a ($\sqrt{7}\times\sqrt{7}$)R19.1$^\circ$ superstructure which has not been observed so far.

cond-mat.mtrl-sci↗