Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interplay between Magnetic and Vestigial Nematic Orders in the Layered
  $J_1$-$J_2$ Classical Heisenberg Model   We study the layered $J_1$-$J_2$ classical Heisenberg model on the square
lattice using a self-consistent bond theory. We derive the phase diagram for
fixed $J_1$ as a function of temperature $T$, $J_2$ and interplane coupling
$J_z$. Broad regions of (anti)ferromagnetic and stripe order are found, and are
separated by a first-order transition near $J_2\approx 0.5$ (in units of
$|J_1|$). Within the stripe phase the magnetic and vestigial nematic
transitions occur simultaneously in first-order fashion for strong $J_z$. For
weaker $J_z$ there is in addition, for $J_2^*<J_2 < J_2^{**}$, an intermediate
regime of split transitions implying a finite temperature region with nematic
order but no long-range stripe magnetic order. In this split regime, the order
of the transitions depends sensitively on the deviation from $J_2^*$ and
$J_2^{**}$, with split second-order transitions predominating for $J_2^* \ll
J_2 \ll J_2^{**}$. We find that the value of $J_2^*$ depends weakly on the
interplane coupling and is just slightly larger than $0.5$ for $|J_z| \lesssim
0.01$. In contrast the value of $J_2^{**}$ increases quickly from $J_2^*$ at
$|J_z| \lesssim 0.01$ as the interplane coupling is further reduced. In
addition, the magnetic correlation length is shown to directly depend on the
nematic order parameter and thus exhibits a sharp increase (or jump) upon
entering the nematic phase. Our results are broadly consistent with predictions
based on itinerant electron models of the iron-based superconductors in the
normal-state, and thus help substantiate a classical spin framework for
providing a phenomenological description of their magnetic properties.

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The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex