A first-principle prediction on the magnetism and electronic structure of Ti-doped CoO with two O vacancies

•Two O vacancies near Ti have an effect on electronic structure of Co14Ti2O14 system.•The system with O vacancies at 1 and 3 positions shows a half-metallic character.•The system with O vacancies at 9 and 11 positions is a spin gapless semiconductor.

The electronic structure and magnetism in Co14Ti2O14 systems are investigated by using the first-principles calculations. The system of 2 × 2 × 2 Co14Ti2O16 supercell doped with Ti at 9 and 11 position shows a half-metallic character with a high spin polarization. Based on the above system, we remove two O atoms to form two O vacancies. The two O vacancies near Ti have a huge effect on the electronic structure and magnetic properties of Co14Ti2O14 system. When O vacancies locate at 1 and 3 positions, the system shows a half-metallic character. For the O vacancies at 6 and 8 positions, the system shows a semiconducting character. The system with O vacancies at 9 and 11 positions is a typical spin gapless semiconductor.

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