LAUSR

Abstract Effect of charge compensation codoping on electronic structure, magnetic and optical absorption of SrNbxTi1-2xFexO3 ((Nb, Fe)-STO) and SrNbxTi1-2xCrxO3 ((Nb, Cr)-STO) within doping concentration x = 0.0625 were investigated by first-principles calculations. Results show that the charge compensation codoping have a significant influence on magnetic and optical properties of SrTiO3 (STO). The (Nb, Fe) and (Nb, Cr) substitutional codoping STO are more easily formed due to the reduced defect formation energy with respect to that of Fe-doped STO and Cr-doped STO, respectively. The n-type Nb-doped STO semiconductor becomes a half-metal after Cr/Fe codoping. It is found that the (Nb, Fe)-STO and (Nb, Cr)-STO show significant ferromagnetic behavior, which are attributed to the stronger magnetic coupling between the induced free electrons and 3d spin states of Fe and Cr impurities in these codoped systems. The (Nb, Fe)-STO and (Nb, Cr)-STO display better absorption than that of Nb-doped STO in the visible light region, which could be new promising photocatalytic materials.