Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Frustrated structural instability in superconducting
  quasi-one-dimensional K$_2$Cr$_3$As$_3$   We present neutron total scattering and density functional theory studies on
quasi-one-dimensional superconducting K$_2$Cr$_3$As$_3$ revealing a frustrated
structural instability. Our first principles calculations find a significant
phonon instability which, under energy minimization, corresponds to a
frustrated orthorhombic distortion. In diffraction studies we find large and
temperature independent atomic displacement parameters which pair distribution
analyses confirms and shows as resulting from highly localized orthorhombic
distortions of the CrAs sublattice and coupled K displacements. These results
suggest a far more complex phase diagram than previously assumed for this
unusual superconductor with the likelihood of subtle interplays of structure,
electron-phonon and magnetic interactions.

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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph