Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Origin of Jahn-Teller distortion and orbital-order in LaMnO3   The origin of the cooperative Jahn-Teller distortion and orbital-order in
LaMnO3 is central to the physics of the manganites. The question is complicated
by the simultaneous presence of tetragonal and GdFeO3-type distortions and the
strong Hund's rule coupling between e_g and t_2g electrons. To clarify the
situation we calculate the transition temperature for the Kugel-Khomskii
superexchange mechanism by using the local density approximation+dynamical
mean-field method, and disentangle the effects of super-exchange from those of
lattice distortions. We find that super-exchange alone would yield T_KK=650 K.
The tetragonal and GdFeO3-type distortions, however, reduce T_KK to 550 K. Thus
electron-phonon coupling is essential to explain the persistence of local
Jahn-Teller distortions to at least 1150 K and to reproduce the occupied
orbital deduced from neutron scattering.

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The categories of this paper are: math-ph
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The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
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The categories of this paper are: stat
0
The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th