Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-charge-orbital ordering in hollandite-type manganites studied by
  model Hartree-Fock calculation   We investigate spin-charge-orbital ordering in a Mn$^{3+}$/Mn$^{4+}$ mixed
valence state on a hollandite-type lattice using unrestricted Hartree-Fock
calculation on a multi-band Mn 3$d$-O 2$p$ lattice model. The calculations show
that the Mn$^{3+}$-Mn$^{4+}$ double exchange interaction, the
Mn$^{3+}$-Mn$^{3+}$ and Mn$^{4+}$-Mn$^{4+}$ superexchange interactions are
ferromagnetic and play important roles to stabilize the charge and orbital
ordering pattern. The most stable charge and orbital ordering pattern is
consistent with the $1\times1\times1$ orthorhombic or monoclinic structure of
K$_{1.6}$Mn$_8$O$_{16}$.

35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph