Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of spin waves in ferromagnetic (Ga,Mn)As   The collective behavior of spins in a dilute magnetic semiconductor is
determined by their mutual interactions and influenced by the underlying
crystal structure. Hence, we begin with the atomic quantum-mechanical
description of this system using the proposed variational-perturbation
calculus, and then turn to the emerging macroscopic picture employing
phenomenological constants. Within this framework we study spin waves and
exchange stiffness in the p-d Zener model of (Ga,Mn)As, its thin layers and
bulk crystals described by the spds* tight-binding approximation. Analyzing the
anisotropic part of exchange, we find that the Dzyaloshinskii-Moriya
interaction may lead to the cycloidal spin arrangement and uniaxial in-plane
anisotropy in thin layers, resulting in a surface-like anisotropy in thicker
films. We also derive and discuss the spin-wave contribution to magnetization
and Curie temperature. Our theory reconstructs the values of stiffness
determined from the temperature dependence of magnetization, but reproduces
only partly those obtained from analyzing precession modes in (Ga,Mn)As thin
films.

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The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th