Tunable Magnetic Scattering Effects at the LaAlO₃/SrTiO₃ Interface by Ionic Liquid Gating

The gating effect achieved by an ionic liquid and its electric double layer allows for charge transfer, which can be an order of magnitude larger than that with conventional dielectrics. However, large charged ions also cause inevitable Coulomb scattering in the conducting channel formed at the interface, which can limit the carrier mobility enhancement. In this work, we study the effect of LaAlO3 thickness on the transport properties in LaAlO3/SrTiO3 heterostructures by ionic liquid gating. We find that the transport properties of the LaAlO3/SrTiO3 interface are dominated by intrinsic interactions rather than LaAlO3 thickness and possible effects of ions in the liquid. We observe a Kondo effect, which is enhanced while increasing the gate voltage. For the smallest thickness of the LAO layer, we also observe a gate-tunable and temperature-dependent anomalous Hall effect, which always emerges near the Kondo temperature. Our experiments pave the way to manipulate the various magnetic interactions at the LaAlO3/SrTiO3 interface.