The electronic structures and absorption spectra of Mn-doped GaAs nanowires in the magnetic field

The electronic structures and absorption spectra of Mn-doped GaAs nanowires in the magnetic field are calculated via eight-band k⋅p theory. During the calculation, the optical transitions satisfying the selection rule of nanowires at different wave vectors are considered. We find that (i) the shape of π absorption spectra is substantially different from that of σ absorption spectra whether the radius is 3 nm or 6 nm, and more strong peaks will appear in π and σ absorption spectra when the radius increases from 3 nm to 6 nm; (ii) the shape of π absorption spectra is almost unchanged even if the magnetic field increases to 30 T, while it can be affected slightly by increasing the concentration of manganese ions; (iii) two σ absorption spectra can be separated by the magnetic field, and the separation between σ+ and σ− absorption spectra will increase as the increase of the magnetic field and the concentration of manganese ions; (iv) the intensities of the first strong peak in σ+ absorption spectra will become larger than that of the first strong peak in σ− absorption spectra gradually as the increase of the magnetic field and the concentration of manganese ions.