Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A gold complex single crystal comprised of nanoporosity and curved
  surfaces   Complex hierarchical shapes are widely known in biogenic single crystals, but
growing of intricate synthetic metal single crystals is still a challenge. Here
we report on a simple method for growing intricately shaped single crystals of
gold, each consisting of a micron-sized crystal surrounded by a nanoporous
structure, while the two parts comprise a single crystal. This is achieved by
annealing thin films of gold and germanium to solidify a eutectic composition
melt at a hypoeutectic concentration (Au-enriched composition). Transmission
electron microscopy and synchrotron submicron scanning diffractometry and
imaging confirms that the whole structure was indeed a single crystal. A
kinetic model showing how this intricate single-crystal structure can be grown
is presented.

26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys