Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: From mixed valence to the Kondo lattice regime   Many heavy fermion materials are known to crossover from the Kondo lattice
regime to the mixed-valent regime or vice-versa as a function of pressure or
doping. We study this crossover theoretically by employing the periodic
Anderson model within the framework of the dynamical mean field theory. Changes
occurring in the dynamics and transport across this crossover are highlighted.
As the valence is decreased (increased) relative to the Kondo lattice regime,
the Kondo resonance broadens significantly, while the lower (upper) Hubbard
band moves closer to the Fermi level. The resistivity develops a two peak
structure in the mixed valent regime: a low temperature coherence peak and a
high temperature 'Hubbard band' peak. These two peaks merge yielding a broad
shallow maximum upon decreasing the valence further. The optical conductivity,
likewise exhibits an unusual absorption feature (shoulder) in the deep
mid-infrared region, which grows in intensity with decreasing valence. The
involvement of the Hubbard bands in dc transport, and of the effective f-level
in the optical conductivity are shown to be responsible for the anomalous
transport properties. A two-band hybridization-gap model, which neglects
incoherent effects due to many-body scattering, commonly employed to understand
the optical response in these materials is shown to be inadequate, especially
in the mixed-valent regime. Comparison of theory with experiment carried out
for (a) dc resistivities of CeRhIn5, Ce2Ni3Si5, CeFeGe3 and YbIr2Si2; (b)
pressure dependent resistivity of YbInAu2 and CeCu6; and (c) optical
conductivity measurements in YbIr2Si2 yields excellent agreement.

1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an