Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical study of archetypical valence-fluctuating Eu-systems   We have investigated the optical conductivity of the prominent valence
fluctuating compounds EuIr2Si2 and EuNi2P2 in the infrared energy range to get
new insights into the electronic properties of valence fluctuating systems. For
both compounds we observe upon cooling the formation of a renormalized Drude
response, a partial suppression of the optical conductivity below 100 meV and
the appearance of a mid-infrared peak at 0.15 eV for EuIr2Si2 and at 0.13 eV
for EuNi2P2. Most remarkably, our results show a strong similarity with the
optical spectra reported for many Ce- or Yb-based heavy fermion metals and
intermediate valence systems, although the phase diagrams and the temperature
dependence of the valence differ strongly between Eu- and Ce-/Yb-systems. This
suggests that the hybridization between 4f- and conduction electrons, which is
responsible for the properties of Ce- and Yb-systems, plays an important role
in valence fluctuating Eu-systems.

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The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
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The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph