Synergistic Effects of Vacancies and Boron Dopants in Tuning the Electronic Structures and Magnetism of SrTiO ₃

The magnetic properties of boron-doped SrTiO 3 (SrTi[Formula: see text]B[Formula: see text]O[Formula: see text] without and with different vacancies (Sr, Ti and O) are investigated through first-principles calculations. The (B, B)-doping prefers to occupy the nearest-neighbor Ti sites in ferromagnetic orders and generates a significantly improved spin magnetization. Spin density distribution changes from uniformly distributed to centrally localized by introducing three types of vacancies, while keeping an approximately equal net magnetic moment of 2[Formula: see text][Formula: see text]. The net magnetic moments are mainly derived from the magnetized O atoms, except in the system of SrTi[Formula: see text]B[Formula: see text]O 3 with oxygen vacancy, where the Ti and O atoms contribute equally to the total magnetic moment. The synergistic effects of strong [Formula: see text]-[Formula: see text] and relatively weak [Formula: see text]-[Formula: see text] hybridizations lead to the asymmetric electronic states and induce magnetic moments. The calculation findings reveal that the combination of vacancies and boron-doping in SrTiO 3 can be an efficient strategy to modulate the half-metallic or metallic ferromagnetism behavior.