Electronic- and band-structure evolution in low-doped (Ga,Mn)As

Abstract

Modulation photoreflectance spectroscopy and Raman spectroscopy have been applied to study the electronic- and band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn doping in the range of low Mn content, up to 1.2%. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap transition energy with increasing Mn content in very low-doped (Ga,Mn)As layers with n-type conductivity are interpreted as a result of merging the Mn-related impurity band with the host GaAs valence band. On the other hand, an increase in the band-gap-transition energy with increasing Mn content in (Ga,Mn)As layers with higher Mn content and p-type conductivity indicates the Moss-Burstein shift of the absorption edge due to the Fermi level location within the valence band, determined by the free-hole concentration. The experimental results are consistent with the valence-band origin of mobile holes mediated ferromagnetic ordering in the (Ga,Mn)As diluted ferromagnetic semiconductor.

20 pages, 5 figures. arXiv admin note: text overlap with arXiv:1012.4760

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Cited by in corpus (4)

• On the origin of magnetism in (Ga,Mn)As: from paramagnetic through superparamagnetic to ferromagnetic phase
• Effect of low-temperature annealing on the electronic- and band-structure of (Ga,Mn)As epitaxial layers
• Bandgap narrowing in Mn doped GaAs probed by room-temperature photoluminescence
• Bismuth doping induced enhancement of the spin-orbit coupling strength in the prototype dilute ferromagnetic semiconductor (Ga,Mn)As: a review