Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermi Contour Disintegration of Quasi-2D Electrons in Parallel Magnetic
  Fields   In a quasi two-dimensional electron system with non-zero layer thickness, a
parallel magnetic field (B||) can couple to the out-of-plane electron motion
and lead to a severe distortion and eventual disintegration of the Fermi
contour. Here we directly and quantitatively probe this evolution through
commensurability and Shubnikov-de Haas measurements on electrons confined to a
40-nm-wide GaAs (001) quantum well. We are able to observe the Fermi contour
disintegration phenomenon, in good agreement with the results of semi-classical
calculations. Experimentally we also observe intriguing features, suggesting
magnetic-breakdown-type behavior when the Fermi contour disintegrates.

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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: econ