Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Frequency dependence of conductivity in the layered In$_4$Se$_3$
  crystals   The frequency dependence of conductivity in In$_4$Se$_3$, pure and with
copper admixture crystals, in the region of nitrogen temperatures is
investigated. It was found out that variable length hops on the localized
levels in the vicinity of Fermi level is pre-dominant mechanism of charge
transfer in the crystals. For pure In$ _4$Se$ _3$ crystals the density of
localized states is $10^{17}-10^{18}$ eV$^{-1}\cdot$cm$^{-3}$, the mean hop
length is 220--350 {\AA}. The reasons for the occurrence of localized states
are considered within the model of a layered crystal as a quasi-disordered
system.

12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin