Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetism in parent Fe-chalcogenides: quantum fluctuations select a
  plaquette order   We analyze magnetic order in iron-chalcogenide Fe$_{1+y}$Te -- the parent
compound of high-temperature superconductor Fe$_{1+y}$Te$_{1-x}$Se$_x$. Neutron
scattering experiments show that magnetic order in this material contains
components with momentum $Q_1=(\pi/2, \pi/2)$ and $Q_2 =(\pi/2, -\pi/2)$ in
Fe-only Brillouin zone. The actual spin order depends on the interplay between
these two components. Previous works argued that spin order is a single-$Q$
state (either $Q_1$ or $Q_2$). Such an order breaks rotational $C_4$ symmetry
and order spins into a double diagonal stripe. We show that quantum
fluctuations actually select another order -- a double $Q$ plaquette state with
equal weight of $Q_1$ and $Q_2$ components, which preserves $C_4$ symmetry but
breaks $Z_4$ translational symmetry. We argue that the plaquette state is
consistent with recent neutron scattering experiments on Fe$_{1+y}$Te.

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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: cs
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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: patt-sol
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The categories of this paper are: econ
30
The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an