Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron-Hole Asymmetry in GdBaCo_{2}O_{5+x}: Evidence for Spin Blockade
  of Electron Transport in a Correlated Electron System   In RBaCo_{2}O_{5+x} compounds (R is rare earth) variability of the oxygen
content allows precise doping of CoO_2 planes with both types of charge
carriers. We study transport properties of doped GdBaCo_{2}O_{5+x} single
crystals and find a remarkable asymmetry in the behavior of holes and electrons
doped into a parent insulator GdBaCo_{2}O_{5.5}. Doping dependences of
resistivity, Hall response, and thermoelectric power reveal that the doped
holes greatly improve the conductivity, while the electron-doped samples always
remain poorly conducting. This doping asymmetry provides strong evidence for a
spin blockade of the electron transport in RBaCo_{2}O_{5+x}.

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The categories of this paper are: hep-th
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The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
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The categories of this paper are: math
10
The categories of this paper are: q-bio