Exchange interaction and ferromagnetism in III-V semiconductors

Abstract

The mechanism of indirect exchange interaction leading to ferromagnetism in magnetically doped III-V semiconductors is considered theoretically. The mechanism is based on the interplay of two interactions: ͑i͒ hybridization of band states with shallow impurity ones, and ͑ii͒ direct exchange coupling between localized spins and the band states. The indirect exchange interaction between two Mn impurities occurs when the wave functions of shallow states associated with the Mn atoms overlap. The mechanism does not rely on degenerate carriers, and therefore can describe the ferromagnetic transition in both degenerate and nondegenerate semiconductors. Ferromagnetic critical temperature has been calculated within the percolation approach, and is in good agreement with available experimental data.

Spintronics and spintronics materials

“…This approach is used for the description of ferromagnetism in such DMS as (Ga,Mn)As, (Ga,Mn)P, and (Ga,Mn)N (see a re view 379 and Refs 79,[380][381][382]. Some of these theories take into account the role of shallow acceptors 383 resonance levels. 384,385 Note that the expression 77,78 (see also Ref.…”

In-plane noncollinear exchange coupling mediated by helical edge states in quantum spin Hall systems

“…9 More recently, people propose that the controllable RKKY interaction can be used to manipulate the quantum states of the local spins, which is a crucial point for the spintronics and quantum computing. 10,11 Thereafter, the RKKY interactions in different spintronic materials, e.g., spin-orbital system [12][13][14] and graphene, [15][16][17][18] have been investigated carefully in order to facilitate the further development of the spintronic devices. Compared with the normal cases, the effective interactions between local spins in these systems exhibit rather different properties.…”

Mixed valence, percolation, and ferromagnetism in transition-metal-doped GaN

“…20 Alternative mechanisms of the interspin interaction rely on excitation transfer through the TM impurity band, the double-exchange mechanism, 7,19 and valence-impurity band transitions. 21,22 The double-exchange mechanism is not efficient if the impurity band is totally filled. This can be taken into account assuming that the magnetic coupling depends on a filling factor: A͑T͒ = A͑1− f͒.…”