Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinetic Monte Carlo simulations inspired by epitaxial graphene growth   Graphene, a flat monolayer of carbon atoms packed tightly into a two
dimensional hexagonal lattice, has unusual electronic properties which have
many promising nanoelectronic applications. Recent Low Energy Electron
Microscopy (LEEM) experiments show that the step edge velocity of epitaxially
grown 2D graphene islands on Ru(0001) varies with the fifth power of the
supersaturation of carbon adatoms. This suggests that graphene islands grow by
the addition of clusters of five atoms rather than by the usual mechanism of
single adatom attachment.
  We have carried out Kinetic Monte Carlo (KMC) simulations in order to further
investigate the general scenario of epitaxial growth by the attachment of
mobile clusters of atoms. We did not seek to directly replicate the Gr/Ru(0001)
system but instead considered a model involving mobile tetramers of atoms on a
square lattice. Our results show that the energy barrier for tetramer break up
and the number of tetramers that must collide in order to nucleate an immobile
island are the important parameters for determining whether, as in the
Gr/Ru(0001) system, the adatom density at the onset of island nucleation is an
increasing function of temperature. A relatively large energy barrier for
adatom attachment to islands is required in order for our model to produce an
equilibrium adatom density that is a large fraction of the nucleation density.
A large energy barrier for tetramer attachment to islands is also needed for
the island density to dramatically decrease with increasing temperature. We
show that islands grow with a velocity that varies with the fourth power of the
supersaturation of adatoms when tetramer attachment is the dominant process for
island growth.

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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: q-bio
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The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-th