Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-resolved electronic structure of EuO across the Curie Temperature   The electronic structure of the ferromagnetic semiconductor EuO is
investigated by means of spin- and angle-resolved photoemission spectroscopy
and density functional theory. Valence bands of EuO exhibit unique properties
of hosting both the fully exchange split Eu $4f$, as well as O $2p$ levels. Our
spin-resolved data directly demonstrates the exchange splitting in O $2p$ and
reveals that, while the macroscopic magnetization of the sample vanishes at the
Curie temperature $T_C$, the experimentally-determined exchange splitting of
the O 2$p$ band persists up to $T_{C}$ if the picture of fluctuating
spin-blocks is assumed. We discuss possible temperature-related spectral
changes by analyzing ferromagnetic and antiferromagnetic phases, directional
effect due to spin-orbit coupling, as well as effects due to sample aging,
unavoidable for this highly reactive material. Our calculations with a Hubbard
$U$ term reveal a complex nature of the local exchange splitting on the oxygen
site and in conduction bands, shining a new light on the interpretation of
previous optical and photoemission spectroscopic results.

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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph