Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metal-Insulator Transition in Two Dimensions in a Nearly Periodic
  Potential   A two-dimensional gas of non-interacting quasiparticles in a nearly periodic
potential is considered at zero temperature. The potential is a superposition
of a periodic potential, induced by the charge density wave of a Wigner
crystal, and a weak random potential due to disorder. There is a
metal-insulator transition that is controlled by the strength of the periodic
potential. The transition is continuous in the presence of randomness. We
evaluate the density of states, which is non-zero at the Fermi energy in the
metallic phase, and the dc conductivity. The latter changes with decreasing
modulation of the periodic potential from 0 to $\sigma\approx2e^2/h$.

19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
2
The categories of this paper are: math