Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of Fe excess on structural, magnetic and superconducting
  properties of single-crystalline Fe(1+x)Te(1-y)Se(y)   Single crystals of Fe(1+x)Te(1-y)Se(y) have been grown with a controlled Fe
excess and Se doping, and the crystal structure has been refined for various
compositions. The systematic investigation of magnetic and superconducting
properties as a function of the structural parameters shows how the material
can be driven into various ground states, depending on doping and the
structural modifications. Our results prove that the occupation of the
additional Fe site, Fe2, enhances the spin localization. By reducing the excess
Fe, the antiferromagnetic ordering is weakened, and the superconducting ground
state is favored. We have found that both Fe excess and Se doping in synergy
determine the properties of the material and an improved 3-dimensional phase
diagram is proposed.

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The categories of this paper are: physics
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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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: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph