Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Structural Probe of the Doped Holes in Cuprate Superconductors   An unresolved issue concerning cuprate superconductors is whether the
distribution of carriers in the CuO(2) plane is uniform or inhomogeneous.
Because the carriers comprise a small fraction of the total charge density and
may be rapidly fluctuating, modulations are difficult to detect directly. Here
we demonstrate that in anomalous x-ray scattering at the oxygen K edge of the
cuprates, the contribution of carriers to the scattering amplitude is
selectively magnified 82 times. This enhances diffraction from the doped holes
by more than 10^3, permitting direct structural analysis of the superconducting
ground state. Scattering from thin films of La(2)CuO(4+x) (Tc = 39 K) at T=(50
+/- 5) K on the reciprocal space intervals (0,0,0.21) -> (0,0,1.21) and
(0,0,0.6) -> (0.3,0,0.6) show a rounding of the carrier density near the
substrate suggestive of a depletion zone or similar effect. The structure
factor for off-specular scattering was less than 3x10-7 e, suggesting an
absence of in-plane hole ordering in this material.

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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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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: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: alg-geom