First-principles calculations of optical and magneto-optical properties of Ga1-xMnxAs and MnAs

We present a first-principles density-functional investigation of the optical and magneto-optical properties of MnxGa1-xAs (with x=0,0.0625, and 1) systems. Our calculated dielectric function, magneto-optical Kerr effect, and magnetic circular dichroism spectra agree reasonably well with existing experimental results. A comparison of the optical and magneto-optical spectra of MnAs in the naturally occurring hexagonal phase and in the cubic zinc-blende structure is made. The differences in the spectral properties of these two phases could aid detection of MnAs in the zinc-blende structure.