Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Defect-induced orbital polarization and collapse of orbital order in
  doped vanadium perovskites   We explore mechanisms of orbital order decay in doped Mott insulators
$R_{1-x}$(Sr,Ca)$_x$VO$_3$ ($R=\,$Pr,Y,La) caused by charged (Sr,Ca) defects.
Our unrestricted Hartree-Fock analysis focuses on the combined effect of
random, charged impurities and associated doped holes up to $x=0.5$. The study
is based on a generalized multi-band Hubbard model for the relevant vanadium
$t_{2g}$ electrons, and includes the long-range (i) Coulomb potentials of
defects and (ii) electron-electron interactions. We show that the rotation of
occupied $t_{2g}$ orbitals, induced by the electric field of defects, is a very
efficient perturbation that largely controls the suppression of orbital order
in these compounds. We investigate the inverse participation number spectra and
find that electron states remain localized on few sites even in the regime
where orbital order is collapsed. From the change of kinetic and superexchange
energy we can conclude that the motion of doped holes, which is the dominant
effect for the reduction of magnetic order in high-$T_c$ compounds, is of
secondary importance here.

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The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
18
The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
6
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: q-alg