Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dual Character of Magnetism in Ferropnictides: Insights from Optical
  Measurements   We investigate the electronic structure of EuFe$_{2}$As$_{2}$ using optical
spectroscopy and first-principles calculations. At low temperature we observe
the evolution of \textit{two} gap-like features, one having a BCS mean-field
behavior and another with strongly non-BCS behavior. Using band structure
calculations, we identify the former with a spin-Peierls-like partial gap in
$d_{yz}$ bands, and the latter with the transition across the large exchange
gap in $d_{xz}/d_{xy}$ bands. Our results demonstrate that the
antiferromagnetism in the ferropnictides is neither fully local nor fully
itinerant, but contains elements of both.

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The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin