Mechanical Properties and Fracture Dynamics of Silicene Membranes
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Mechanical Properties and Fracture Dynamics of Silicene Membranes
Tiago Botari1, Eric Perim1, P. A. S. Autreto1, Ricardo Paupitz2, and Douglas S. Galvao1
1
Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas, 13083-970, Campinas, São Paulo, Brazil. 2
Departamento de Física, IGCE, Universidade Estadual Paulista, UNESP, 130506-900, Rio Claro, SP, Brazil.
ABSTRACT
The advent of graphene created a new era in materials science. Graphene is a twodimensional planar honeycomb array of carbon atoms in sp2-hybridized states. A natural question is whether other elements of the IV-group of the periodic table (such as silicon and germanium), could also form graphene-like structures. Structurally, the silicon equivalent to graphene is called silicene. Silicene was theoretically predicted in 1994 and recently experimentally realized by different groups. Similarly to graphene, silicene exhibits electronic and mechanical properties that can be exploited to nanoelectronics applications. In this work we have investigated, through fully atomistic molecular dynamics (MD) simulations, the mechanical properties of single-layer silicene under mechanical strain. These simulations were carried out using a reactive force field (ReaxFF), as implemented in the LAMMPS code. We have calculated the elastic properties and the fracture patterns. Our results show that the dynamics of the whole fracturing processes of silicene present some similarities with that of graphene as well as some unique features.
INTRODUCTION
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The chemistry of carbon is very rich, the three different hybridization states (sp, sp2 and sp3) allow the generation of a large number of different structures, such as: diamond (sp3), graphite, graphene (single-layer graphite), fullerenes and nanotubes (sp2) [1], and graphynes (sp) [2-4]. The carbon-based structures of reduced dimensionality (such as, fullerenes and nanotubes) have been shown to exhibit some extraordinary structural, thermal and electronic properties. Another spectacular example of this is graphene [5]. The advent of graphene created a new era in materials science. Due to its unique electronic and mechanical properties, graphene is considered as the basis for a new electronics [5-7]. However, in its pristine form graphene is a zero bandgap semiconductor, what limits its use in some transistor applications [7]. In part because of this, there is a renewed interest in other possible graphene-like structures, based on carbon or other chemical elements. Graphene (see Figure 1) is a two-dimensional (planar) honeycomb array of carbon atoms. A natural question is whether other IV-group elements of the periodic table (such as, silicon and germanium), could also form graphene-like structures. For these elements the graphene equivalent structures are called silicene [8] (see Figure 1) and germanene [9]. Silicene, a single-layer two-dimensional honeycomb silicon sheet, was first predicted to exist based on ab initio calculations in 1994 [8]. It was recently synthesized by different groups [1015]. Ge
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