Role of Oxygen Vacancies in transposing the Electronic Properties of a Nonmagnetic Band Insulator KTaO₃

Potassium Tantalate (KTaO₃) based 2-DEG is a potential platform for investigating spin-orbit coupling driven novel electronic and magnetic phenomena. In KTaO₃ (KTO), oxygen vacancies emerge new exotic and collective behaviors like the observation of anomalous and topological Hall effect, an insulator to metal transition, etc. Our ab-initio calculations show that the isolated oxygen vacancies in KTO behave like a magnetic impurity, transforming the system from non-magnetic to a magnetic state. Noncollinear calculations reveal that isolated oxygen vacancies in KTO lead to non-trivial spin texture formation in real and momentum space. The local magnetic moments around the oxygen vacancies can cause skew scattering of the electrons, which originate the observation of the anomalous Hall effect in oxygen-deficient KTO. The ab-initio calculations also show that the oxygen vacancies tend to form a linear cluster around the Ta atoms.