The potentially crucial role of quasi-particle interferences for the growth of silicene on graphite

Abstract

A comprehensive picture of the initial stages of silicene growth on graphite is drawn. Evidence is shown that quasiparticle interferences play a crucial role in the formation of the observed silicene configurations. We propose, on one hand, that the charge modulations caused by those quantum interferences serve as templates and guide the incoming Si atoms to self-assemble to the unique (√3×√3)R30° honeycomb atomic arrangement. On the other hand, their limited extension limits the growth to about 150 Si atoms under our present deposition conditions. The here proposed electrostatic interaction finally explains the unexpected stability of the observed silicene islands over time and with temperature. Despite the robust guiding nature of those quantum interferences during the early growth phase, we demonstrate that the window of experimental conditions for silicene growth is quite narrow, making it an extremely challenging experimental task. Finally, it is shown that the experimentally observed three-dimensional silicon clusters might very well be the simple result of the end of the silicene growth resulting from the limited extent of the quasiparticle interferences. Graphical Table of Contents Charge modulations caused by quantum interferences (QI) on graphene guide Si atoms to selfassemble to the unique (√3×√3)R30° honeycomb atomic arrangement. The limited extend of those QI leads to the experimentally observed transition from 2D to 3D growth at the outskirts of the silicene islands.

Epitaxial growth and structural properties of silicene and other 2D allotropes of Si

“…142 143 In order to solve the apparent contradiction with experimental results that indicate the formation of a single phase with higher strain, DFT calculations for small silicene islands have been undertaken. 144 It appears that for islands below a size of 50 atoms, the ð ffiffiffi…”

“…143 In order to solve the apparent contradiction with experimental results that indicate the formation of a single phase with higher strain, DFT calculations for small silicene islands have been undertaken. 144 It appears that for islands below a size of 50 atoms, the reconstruction is more stable than the one. Ab initio molecular dynamics (AIMD) simulations showed that the incoming flux of Si atoms could prevent the 2D islands to convert into 3D islands.…”

“…However the needed ux is orders of magnitude higher than the experimental one. 144 A simple explanation has been however given. It was shown that the observed apparent ð ffiffiffi 3 p  ffiffiffi 3 p ÞR30 reconstruction is caused by charge density modulations in the HOPG surface at the vicinity of the 3D Si clusters.…”

Electrical-gate-controlled giant tunneling magnetoresistance and its quasi-periodic oscillation in an interlaced magnetic-electric silicene superlattice

“…10 Several groups have experimentally synthesized silicene in recent years and characterized its basic properties. [11][12][13] Through a theoretical study, it has been found that silicene has a quantum abnormal Hall effect and photoinduced topological phase transition. 14,15 In addition, Yokoyama 16 demonstrated that a complete polarization valley and spin transport could be realized in ferromagnetic silicene.…”

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

“…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. − 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 . The restricted extension of these QI limits the growth to very tiny 2D Si-ene flakes in the nanometer range and causes the transition to a 3D growth mechanism resulting in small 3D clusters at the outskirts of the tiny 2D Si-ene areas as observed experimentally. , The size limitation also originates from the presence of high defect densities on the HOPG substrate, which favor both intercalation of silicon underneath the top surface (even at room temperature), resulting in the formation of buried silicene, , and the preferential defect-assisted 3D cluster nucleation at the origin of the transition between layer-by-layer growth and Volmer–Weber growth.…”