First principles calculations on magnetic and optical properties of (Cr, Mn) co-doped 4H-SiC.

By means of first-principles calculations, we investigate the effect of Cr, Mn impurities on the magnetic and optical properties of 4H-SiC. We find the Cr atom monodoped 4H-SiC has the more stable configuration. The Cr monodoped, Co monodoped, (Cr, Co) co-doped and (Cr, Co, V_Si) co-doped 4H-SiC system all can induce magnetism. The results indicate that (Cr, Co) co-doped 4H-SiC has the strongest ferromagnetism with ΔE of −489.7 meV. The magnetic coupling between the magnetic moments and the strong ferromagnetic coupling caused by Cr and Mn doping can be attributed to the p-d hybrid interaction. The silicon vacancy has a negative influence on the local magnetic moments of Mn atom of (Cr, Mn) co-doped 4H-SiC. When transition metals (TM = Cr, Mn atoms) are introduced into 4H-SiC, the imaginary part of the dielectric function and the adsorption spectrum are both red-shifted with the change of band gap. The results provide a new route for the potential applications of dilute magnetic semiconductors in spintronic devices by transition metal (TM = Cr, Mn atoms) doped 4H-SiC. [ABSTRACT FROM AUTHOR]