Electric field control of anomalous Hall effect in CaIrO${}_3$/CaMnO${}_3$ heterostructure

We demonstrate an electric field control of anomalous Hall effect emerging in CaIrO${}_3$/CaMnO${}_3$ heterostructures. We fabricate both electron-type and hole-type carrier samples by tuning epitaxial strain and then control the carrier density in CaIrO${}_3$ layer via electric double layer gating technique. As the Fermi energy of CaIrO${}_3$ is tuned close to the Dirac line node, anomalous Hall conductivity is enlarged in both carrier-type samples. This result reveals that the anomalous Hall effect comes from the intrinsic origin reflecting the Dirac like dispersion in CaIrO${}_3$. We propose that band splitting induced by the interface ferromagnetism yields several band crossing points near the Dirac line node. These points play as a source of the Berry curvature and contribute to the anomalous Hall effect.