Highly Biaxially Strained Silicene on Au(111)

Abstract

Many of graphene’s remarkable properties arise from its linear dispersion of the electronic states, forming a Dirac cone at the K points of the Brillouin zone. Silicene, the 2D allotrope of silicon, is also predicted to show a similar electronic band structure, with the addition of a tunable bandgap, induced by spin–orbit coupling. Because of these outstanding electronic properties, silicene is considered as a promising building block for next-generation electronic devices. Recently, it has been shown that silicene grown on Au(111) still possesses a Dirac cone, despite the interaction with the substrate. Here, to fully characterize the structure of this 2D material, we investigate the vibrational spectrum of a monolayer silicene grown on Au(111) by polarized Raman spectroscopy. To enable a detailed ex situ investigation, we passivated the silicene on Au(111) by encapsulating it under few layers hBN or graphene flakes. The observed spectrum is characterized by vibrational modes that are strongly red-shifted with respect to the ones expected for freestanding silicene. By comparing low-energy electron diffraction (LEED) patterns and Raman results with first-principles calculations, we show that the vibrational modes indicate a highly (>7%) biaxially strained silicene phase.

Magnetism in Au-Supported Planar Silicene

“…However, presence of the substrate can effectively suppress the PJT effect, and the planar supported form of silicene can exist [10,24,25]. This has been demonstrated in the case of silicene prepared on Au(111) films grown on Si(111) [21,26] and on mica substrates [27].…”

Van der Waals Heteroepitaxy of Air-Stable Quasi-Free-Standing Silicene Layers on CVD Epitaxial Graphene/6H-SiC

“…46,47 There again, strong interactions with the substrates were demonstrated both theoretically and experimentally. 48,49 More recently, to overcome this limitation various experiments have been carried out on C-based inert substrates such as highly oriented pyrolytic graphite (HOPG) with hexagonal atomic arrangements. [50][51][52][53] On this substrate, the results demonstrated that the charge modulations caused by quantum interferences (QI) serve as templates and guide the incoming Si atoms to self-assemble in 2D clusters.…”

“…Consequently, the investigations naturally shifted to alternative metal substrates such as Ir(111), Ru (0001), Pt(111), Pb(111), and Au(111). , There again, strong interactions with the substrates were demonstrated both theoretically and experimentally. , …”

Automatic indexing of two-dimensional patterns in reciprocal space

“…Crystal structure identification of both thin organic and inorganic films, especially two-dimensional (2D) materials beyond graphene, attracts considerable interest, amongst others, in potential electronic applications and pharmaceutical science [1][2][3][4][5][6][7][8][9][10]. The presence of a single crystalline substrate surface during the crystallization process can induce new types of molecular or atomic packing because the substrate tends to act as a template for the crystallization process.…”

“…Further, if molecular crystals are epitaxially grown on singlecrystalline substrates, multiple preferred orientations of the adsorbate, several symmetry-related in-plane alignments, and the emergence of unknown polymorphs can occur [17][18][19][20]. For inorganic epitaxial layers also unknown surface-induced polymorphs are frequently observed, such as the formation of a 2D network consisting of so-called blue phosphorene and gold linker atoms [8] or the growth of a strained silicene monolayer on Au(111) [9].…”