Electronic Structure and Magnetic Properties of V-Monodoped and (V, Al)-Codoped 4H-SiC

Abstract

Electronic structure and magnetic properties of vanadium (V)-doped 4H-SiC are researched by using the first-principle plane wave pseudopotential method based on density functional theory. Ten kinds of doping position are calculated and the most stable configuration is found. The results indicate that V-monodoped 4H-SiC favors a spin-polarized state and the magnetic moment mainly comes from the unpaired 3d electronic of V atoms. Several doping configurations studied suggest the existence of ferromagnetic coupling between V dopant. Ferromagnetic order is activated by V doping via a V0:3d-C:2p-V7:3d coupling chain. Hybridization occurs between p − d orbitals. The doped V atom will induce additional holes carrier into the 4H-SiC. Al itself has no contribution to the magnetic moment, whereas V- and Al-codoped 4H-SiC can induce spin polarization, which reveals that the FM stability is reduced significantly by Al codoping. The calculated electronic structure implies that the presence of Si vacancies (V si ) weakens the FM state of V- and V si -codoped 4H-SiC.