Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shape Transition in the Epitaxial Growth of Gold Silicide in Au Thin
  Films on Si(111)   Growth of epitaxial gold silicide islands on bromine-passivated Si(111)
substrates has been studied by optical and electron microscopy, electron probe
micro analysis and helium ion backscattering. The islands grow in the shape of
equilateral triangles up to a critical size beyond which the symmetry of the
structure is broken, resulting in a shape transition from triangle to
trapezoid. The island edges are aligned along $Si[110]$ directions. We have
observed elongated islands with aspect ratios as large as 8:1. These islands,
instead of growing along three equivalent [110] directions on the Si(111)
substrate, grow only along one preferential direction. This has been attributed
to the vicinality of the substrate surface.

22
The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
2
The categories of this paper are: math