Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magneto-optical evidence of the percolation nature of the
  metal-insulator transition in the 2D electron system   We compare the results of the transport and time-resolved
magneto-luminescence measurements in disordered 2D electron systems in
GaAs-AlGaAs heterostructures in the extreme quantum limit, in particular, in
the vicinity of the metal-insulator transition (MIT). At filling factors $\nu
<1$, the optical signal has two components: the single-rate exponentially
decaying part attributed to a uniform liquid and a power-law long-living tail
specific to a microscopically inhomogeneous state of electrons. We interprete
this result as a separation of the 2D electron system into a liquid and
localized phases, especially because the MIT occurs strikingly close to those
filling factors where the liquid occupies ${1\over 2}$ of the sample area (the
percollation threshold condition in two-component media).

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The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci