Effects Of O Defects On The Magnetism And Electronic Structure Of Ti-doped CoO: A First-principle Prediction

The electronic structure and magnetism in CoTiO systems with O defects are investigated by using the first-principles calculation.The pure CoO is an antiferromagnetic semiconductor.The system of Ti doped at 9 and 11 position show a half-metallic character.The characters of systems that the O defect behind Ti have a great effect on the Ti magnetic moment by the electron transfer.When the O defects at 6 and 9 position,the Ti magnetic moment is very small and the systems are semiconductors.For the O defect at 1 position,the Ti magnetic moment is smaller than Co14Ti2O16 system,show a metallic character that makes its conductivity enhanced.The system with O defect at 2 position shows a shows a half-metallic character due to the strong hybridization between Ti and Co.Moreover,the O defect in far position shows a different result.The system o f O defect at 5 position show the metallic characteristic,the systems of O defect at 13 and 14 positions show a half-metallic character.For Co₁₄Ti₂O₁₄ systems with two O defects,the two O defects near Ti have a huge effect on the electronic structure and magnetic properties of the systems.When O defects locate at 1 and 3 positions,the system shows a half-metallic character.For the O defects at 6 and 8 positions,the system shows a semiconducting character,but it can easily to achieve 100% spin polarization if a small energy has been given.The system of O defects at 9 and 11 positions is a typical spin gapless semiconductor.