Electronic structures and magnetic properties of (Al, Cr) co-doped 4H-SiC: a first-principles study

Abstract

Electronic and magnetic properties of Cr-doped 4H silicon carbide (4H-SiC) with Al and silicon vacancies (VSi) are studied by first principles calculations. Our results indicate that the (Cr, VSi)-codoped 4H-SiC favours ferromagnetic (FM) ground state, which is enhanced by the nearest-neighboring VSi while is weakened at other positions. For (Cr, Al)-codoped 4H-SiC system, all configurations are ferromagnetic ground state and the stability is greatly enhanced. It is found that indirect ferromagnetic coupling between Cr cations through the hybridization between Cr:3d and Si:3p, C:2p orbitals leads to a Cr1:3d-C:2p-Cr2:3d coupling chain. We also investigated silicon vacancy induced in (Cr, Al)-codoped 4H-SiC system, the results indicate that all configurations are antiferromagnetic states. Our research gives an effective method to investigate the ferromagnetism materials’ doping effect, which benefits for the design of 4H-SiC dilute magnetic semiconductors in magnetism materials.