Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Formation of nano-size Cr layers on LiNbO$_3$ crystal surfaces by
  dissimilar electric charges   Morphology of metal thin layers deposited on polished surfaces of LiNbO$_3$
crystal with dissimilar electric charges has been studied using various methods
of vacuum evaporation. The principal goal of the work is to optimizemethods of
thin metal coating deposition applied to polar surfaces of LiNbO$_3$ crystal.
The conducted research has demonstrated that Cr deposition on LiNbO$_3$ crystal
faces is characterized by dissimilar polarity results in growth difference
conditions of Cr films. The principal role here is played by the sign of the
electric charge on the crystal surface along with the type (thermal or
magnetron) and conditions observed during sputtering (deposition rate,
substrate temperature etc).

27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ