Theory of spin waves in ferromagnetic (Ga,Mn)As

Abstract

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.

17 pages, 12 figures (added Eq. 36, replaced Fig. 10)

References in corpus (10)

• Theory of ferromagnetic (III,Mn)V semiconductors
• Interplay between carrier localization and magnetism in diluted magnetic and ferromagnetic semiconductors
• Hole states in wide band-gap diluted magnetic semiconductors and oxides
• Light-Induced Magnetic Precession in (Ga,Mn)As Slabs: Hybrid Standing-Wave Damon-Eshbach Modes
• Magnetic spin excitations in diluted ferromagnetic systems: the case of $G{a}_{1-x}M{n}_{x}As$
• Magnetic anisotropy of epitaxial (Ga,Mn)As on (113)A GaAs
• Influence of band structure effects on domain-wall resistance in diluted ferromagnetic semiconductors
• Magnetic Anisotropy, Spin Pinning and Exchange Constants of (Ga,Mn)As films
• Magnitude and crystalline anisotropy of hole magnetization in (Ga,Mn)As
• Spin dynamics in the diluted ferromagnetic Kondo lattice model

Cited by in corpus (1)

• Thermodynamic and thermoelectric properties of (Ga,Mn)As and related compounds