Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the nature of ferromagnetism in Ga_{1-x}Mn_xAs semiconductors   We have performed ab initio calculations within the density-functional theory
for Ga_{1-x}Mn_xAs diluted semiconductors. Total energy results unambiguously
show that a quasi-localized down-spin hole, with strong p-like character,
surrounds the fully polarized Mn up-spin d^5-electrons. Calculations indicate
that the holes form an essentially dispersionless impurity band, thus rendering
effective-mass descriptions of hole states open to challenge. We obtain
estimates both for the s = 1/2 hole and S = 5/2 Mn exchange coupling, and for
the distance dependence of the effective Mn-Mn exchange interaction. Results
demonstrate that the effective Mn-Mn coupling is always ferromagnetic, thus
non-RKKY, and intermediated by the antiferromagnetic coupling of each Mn spin
to the holes.

10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th