Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transport and percolation in a low-density high-mobility two-dimensional
  hole system   We present a study of the temperature and density dependence of the
resistivity of an extremely high quality two-dimensional hole system grown on
the (100) surface of GaAs. For high densities in the metallic regime ($p\agt 4
\times 10^{9}$ cm$^{-2}$), the nonmonotonic temperature dependence ($\sim
50-300$ mK) of the resistivity is consistent with temperature dependent
screening of residual impurities. At a fixed temperature of $T$= 50 mK, the
conductivity vs. density data indicates an inhomogeneity driven
percolation-type transition to an insulating state at a critical density of
$3.8\times 10^9$ cm$^{-2}$.

9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph