Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First Principles Calculation of Helical Spin Order in Iron Perovskite
  SrFeO3 and BaFeO3   Motivated by recent discovery of ferromagnetism in cubic perovskite BaFeO3
under small magnetic field, we investigate spin order in BaFeO3 and
isostructual SrFeO3 by the first principles calculation. The on-site Coulomb
and exchange interactions are necessary for the helical spin order consistent
with experiments. SrFeO3 exhibits stable G-type helical order, while A- and
G-type helical orders in BaFeO3 are almost degenerate at short propagating
vector with tiny energetic barrier with respect to ferromagnetic spin order,
explaining ferromagnetism under small field. The results are consistent with
model calculation where negative charge-transfer energy is explicitly taken
into account.

35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess