Keywords: 
• 稀磁半导体 /
• 氧空位 /
• 双交换

Abstract: Dilute magnetic semiconductors have auracted much attention because of their potential applications in spintronics.In this paper, the effects of oxygen vacancy on total energy and magnetism in Co-doped T1O_2 are investigated using the density functional theory. The energy of the system with a shorter Co-Co distance is higher than that with larger Co-Co distance after introducing oxygen vacancy. Oxygen vacancy trends to congregate around the Co cations.Moreover,the strength of exchange couple reduces in the system with a shorter Co-Co distance after introducing oxygen vacancy.For the system with a larger Co-Co distance,the exchange couple between two Co impurities is anti-ferromagnetic if oxygen vacancy is located at the basal site of octahedron containing Co,and ferromagnetic if oxygen vacancy is located at the apical site of octahedron containing Co.