Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Landau Level Crossings and Extended-State Mapping in Magnetic
  Two-dimensional Electron Gases   We present longitudinal and Hall magneto-resistance measurements of a
``magnetic'' two-dimensional electron gas (2DEG) formed in modulation-doped
Zn$_{1-x-y}$Cd$_{x}$Mn$_{y}$Se quantum wells. The electron spin splitting is
temperature and magnetic field dependent, resulting in striking features as
Landau levels of opposite spin cross near the Fermi level. Magnetization
measurements on the same sample probe the total density of states and Fermi
energy, allowing us to fit the transport data using a model involving extended
states centered at each Landau level and two-channel conduction for spin-up and
spin-down electrons. A mapping of the extended states over the whole quantum
Hall effect regime shows no floating of extended states as Landau levels cross
near the Fermi level.

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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: eess
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
3
The categories of this paper are: physics