Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of Ferromagnetic Metal to Paramagnetic Insulator Transition i in
  R_{1-x}A_{x}MnO_{3}   The double-exchange model for the Mn oxides with orbital degeneracy is
studied with including on-site Coulomb repulsion, Jahn-Teller (J-T) coupling
and doping-induced disorder. In the strong interaction limit, it is mapped onto
a single-band Anderson model, in which all scattering mechanisms can be treated
on an equal footing. A sharp rise in the mean square fluctuation of lattice
distortions is found near the Curie temperature $T_c$, in agreement with
experiments. We show that the spin and J-T disorders lead to a metal-insulator
transition (MIT) only at low carrier density. The MIT observed in samples with
$0.2\leq x<0.5$ can be explained by further including the disorder effect of
cation size mismatch.

2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom