Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic structure, spin state, and magnetism of the square-lattice
  Mott insulator La2Co2Se2O3 from first principles   Electronic and magnetic structures of the newly synthesized cobalt
oxyselenide La2Co2Se2O3 (structurally similar to the superconducting iron
pnictides) are studied through density functional calculations. The obtained
results show that this material is a Mott insulator, and that it has a very
stable Co2+ high-spin ground state with a t2g-like orbital ordering, which is
substantiated by the calculated crystal-field excitation energies. The square
lattice of the Co2+ spins is found to have a strong antiferro (a weak ferro)
magnetic coupling for the second nearest neighbors (2nn) via O (Se2) and an
intermediate antiferro one for the 1nn, with the strength ratio about 10:1:3.
The present results account for the available experimental data of magnetism,
and the prediction of a planar frustrated (2x2) antiferromagnetic structure
would motivate a new experiment.

6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin