Stabilized silicene within bilayer graphene: A proposal based on molecular dynamics and density-functional tight-binding calculations

Physical Review B (Impact Factor: 3.66). 01/2014; 89(2). DOI: 10.1103/PhysRevB.89.024107
Source: arXiv

ABSTRACT Free standing silicene is predicted to display comparable electronic
properties as graphene. However, the yet synthesized silicene-like structures
have been only realized on different substrates which turned out to exhibit
versatile crystallographic structures that are very different from the
theoretically predicted buckled phase of freestanding silicene. This calls for
a different approach where silicene is stabilized using very weakly interacting
surfaces. We propose here a novel route by using graphene bilayer as a
scaffold. The confinement between the flat graphene layers results in a planar
clustering of Si atoms with small buckling, which is energetically unfavorable
in vacuum. Buckled hexagonal arrangement of Si atoms similar to free-standing
silicene is observed for large clusters, which, in contrast to Si atoms on
metallic surfaces, is only very weakly van der Waals coupled to the graphene
layers. These clusters are found to be stable well above room temperature. Our
findings, which are supported by density functional tight-binding calculations,
show that intercalating bilayer graphene with Si is a favorable route to
realize silicene.

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    ABSTRACT: As graphene became one of the most important materials today, there is a renewed interest on others similar structures. One example is silicene, the silicon analogue of graphene. It share some the remarkable graphene properties, such as the Dirac cone, but presents some distinct ones, such as a pronounced structural buckling. We have investigated, through density functional based tight-binding (DFTB), as well as reactive molecular dynamics (using ReaxFF), the mechanical properties of suspended single-layer silicene. We calculated the elastic constants, analyzed the fracture patterns and edge reconstructions. We also addressed the stress distributions, unbuckling mechanisms and the fracture dependence on the temperature. We analysed the differences due to distinct edge morphologies, namely zigzag and armchair.
    Physical Chemistry Chemical Physics 08/2014; · 4.20 Impact Factor

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May 15, 2014