First-principles study of electronic structures and ferromagnetism in (Cr, X) (X= Ga, In) co-doped 4H-SiC

Electronic structures and magnetic properties for (Cr, X) (X = Ga, In) co-doped 4H silicon carbide (SiC) are studied by first-principles calculations. Our results show that all configuration of (Cr, X) (X = Ga, In) co-doped 4H-SiC are favor ferromagnetic state. The (Cr, Ga-4) and (Cr, In-4 ) configurations are the most stable one with Delta E-FM of -224.9 meV and -269.6 meV, respectively. Based on the mean-field approximation, the ferromagnetic Curie temperatures (T-C ) are estimated to be 579 K and 695 K, respectively. The ferromagnetism can be attributed to strong p-d hybridization interaction between Cr atoms and their nearest neighbor C atoms. Due to the interaction between the holes introduced by Ga atoms and their surrounding C atoms, doping with Ga and In atoms could decrease the total magnetic moments and increase the ferromagnetic stability. Additionally, we find that the magnetic moments induced by Cr atoms strongly depend on Ga (In) atom's location. The element doping of homologous group is an effective method to precisely regulate the electronic properties. Our results indicate that (Cr, X) (X = Ga, In) co-doped 4H-SiC system may be the promising ferromagnetic materials for spin injection applications. And our work of homologous elements doping can also guide the experiment to a certain extent.