Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metal-insulator transitions: Influence of lattice structure, Jahn-Teller
  effect, and Hund's rule coupling   We study the influence of the lattice structure, the Jahn-Teller effect and
the Hund's rule coupling on a metal-insulator transition in AnC60 (A= K, Rb).
The difference in lattice structure favors A3C60 (fcc) being a metal and A4C60
(bct) being an insulator, and the coupling to Hg Jahn-Teller phonons favors
A4C60 being nonmagnetic. The coupling to Hg (Ag) phonons decreases (increases)
the value Uc of the Coulomb integral at which the metal-insulator transition
occurs. There is an important partial cancellation between the Jahn-Teller
effect and the Hund's rule coupling.

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The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
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The categories of this paper are: eess
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin