Oxygen Vacancy-Induced Anomalous Hall Effect in a Nominally Non-magnetic Oxide

The anomalous Hall effect, a hallmark of broken time-reversal symmetry and spin–orbit coupling, is frequently observed in magnetically polarized systems. However, its realization in nominally non-magnetic systems remains elusive. Here, we report on the observation of the anomalous Hall effect in nominally non-magnetic KTaO3. Anomalous Hall effect emerges in reduced KTaO3 and shows an extrinsic to intrinsic crossover. A paramagnetic behavior is observed in reduced samples and confirmed using first principles calculations. The observed anomalous Hall effect follows the oxygen vacancy-induced magnetization response, suggesting that the localized magnetic moments of the oxygen vacancies scatter conduction electrons asymmetrically and give rise to the anomalous Hall effect. The anomalous Hall conductivity is found to be insensitive to the scattering rate in the low temperature limit (T < 5 K), implying that the Berry curvature of the electrons on the Fermi surface controls the anomalous Hall effect. Our observations provide a detailed picture of many-body interactions, which trigger the anomalous Hall effect in a non-magnetic system.

Duke Scholars

Author Divine P Kumah Physics