Abstract:
We examine the effect of Coulomb correlations in diluted ferromagnetic III-V semiconductors using the LSDA+U correlated band theory method. We show that Hubbard U plays an important role in semiconductor host valence band. We present the results of supercell calculations by the FP-LAPW and TB-LMTO-CPA methods for Ga_1-xMn_xAs and Ga_1-xMn_xN alloys. For Ga_1-xMn_xAs, we find a reasonable increase of d-Mn binding energy in agreement with the experiment. For Ga_1-xMn_xN alloy, an account of the Hubbard U is even more important, moving the sharp d peak from the top into the body of the valence band. Based on the calculated electronic structure, we determine exchange interactions between magnetic moments and discuss the role of electron correlations on Curie temperature.