Multilayer silicene: clear evidence of Ag-terminated bulk silicon

Abstract

The existence of silicite, a new allotrope of silicon based on a stacking of hexagonal silicene planes is one of the most discussed topic in the field of 2D materials. Using grazing incidence X-ray diffraction (GIXD), we have followed in situ the growth of Si films on Ag(111) in the low temperature growth regime (510-520 K). GIXD experiments demonstrate that Si films have a diamond-like structure, with an averaged lattice constant slightly different from bulk Si. The diffracted intensities associated with the Si films are well reproduced by the Ag/Si(111)     30 3 3 R honeycomb chain model, whereas models with Ag-free Si surfaces fail to reproduce the experimental data.

The mechanism for the stabilization and surfactant properties of epitaxial silicene

“…both Ag and Si atoms lying on a silicon layer in a structure analogous to the Si(111) 44,45,[50][51][52]. This corresponds to the present ML+Si/Ag and BL+Si/Ag structures and, indeed, the corresponding simulated STM images (Figure 2).…”

“…[32][33][34][35][36][37][38][39][40] However, these results have been questioned by further independent experimental studies, concluding that the multilayer Si films structure is similar to the diamond-like structure of bulk Si, and that Ag atoms segregates at the surface during growth. [41][42][43][44][45] The exact termination of the surface remains also debated. Reconstructions involving only silicon atoms have been suggested on the basis of experimental and simulation results.…”

Structure and stability of silicene on Ag(111) reconstructions from grazing incidence x-ray diffraction and density functional theory

“…Depending on growth temperature and deposition rate [19,22] R when referred to a Si(111) plane, was initially assigned to a silicon monolayer [30,31]. Later, it has been revealed that this reconstruction corresponds to the termination of a thicker film, with a defective bulklike Si structure [25,[32][33][34][35][36][37].…”

Resonance Raman Spectroscopy of Silicene and Germanene

“…These structures were predicted to be stable by density functional theory, 1,2 and fabricated on metallic substrates amid intensive experimental pursuit over the past decade. [3][4][5][6][7][8][9][10][11] While synthesis of free-standing monolayers is still not accomplished, recent studies have shown that both silicene 12 and germanene 13 monolayers synthesized on metallic surfaces exhibit Dirac-like bands. Moreover, these hybrid structures were already used to fabricate transistors from both silicene 14 What sets silicene and germanene apart from their carbon counterpart 16 is that these structures exhibit a sublattice buckling, that is, the A and B sublattices of the honeycomb structure are vertically shifted relative to one another as shown in Fig.…”