Magnetic circular dichroism in GaxMn1−xAs: Theoretical evidence for and against an impurity band
نویسندگان
چکیده
Magneto-optical properties of the ferromagnetic semiconductor GaMnAs are studied in a material-specific multiband tight-binding approach. Two realistic models are compared: one has no impurity band while the other shows an impurity band for low Mn concentrations. The calculated magnetic circular dichroism MCD is positive for both models proving that, unlike previously asserted, the observed positive MCD signal is inconclusive as to the presence or absence of an impurity band in GaMnAs. The positive MCD is due to the antiferromagnetic p-d coupling and the transitions into the conduction band.
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