Electronic structure of (Ga,Mn)As revisited

Abstract

The detailed nature of electronic states mediating ferromagnetic coupling in dilute magnetic semiconductors, specifically (Ga,Mn)As, has been an issue of long debate. Two confronting models have been discussed emphasizing host band vs. impurity band carriers. Using angle resolved photoemission we are for the first time able to identify a highly dispersive Mn-induced energy band in (Ga,Mn)As. Our results show that the electronic structure of the (Ga,Mn)As system is significantly modified from that of GaAs throughout the valence band. Close to the Fermi energy, the presence of Mn induces a strong mixing of the bulk bands of GaAs, which results in the appearance of a highly dispersive band in the gap region of GaAs. For Mn concentrations above 1% the band reaches the Fermi level, and can thus host the delocalized holes needed for ferromagnetic coupling. Overall, our data provide a firm evidence of delocalized carriers belonging to the modified host valence band.

References in corpus (11)

• Dilute ferromagnetic semiconductors: Physics and spintronic structures
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• Impurity Band Conduction in a High Temperature Ferromagnetic Semiconductor
• Unveiling the impurity band inducing ferromagnetism in magnetic semiconductor (Ga,Mn)As
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• Systematic study of Mn-doping trends in optical properties of (Ga,Mn)As
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• Fermi level position, Coulomb gap, and Dresselhaus splitting in (Ga,Mn)As
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• Photoemission studies of the annealing induced modifications of (Ga,Mn)As

Cited by in corpus (4)

• On the origin of magnetism in (Ga,Mn)As: from paramagnetic through superparamagnetic to ferromagnetic phase
• Interplay between localization and magnetism in (Ga,Mn)As and (In,Mn)As
• Element- and momentum-resolved electronic structure of the dilute magnetic semiconductor manganese doped gallium arsenide
• Electronic properties of Bi-doped GaAs(001) semiconductors