Gate-tuned anomalous Hall effect driven by Rashba splitting in intermixed LaAlO3/GdTiO3/SrTiO3

N Lebedev; M Stehno; A Rana; P Reith; N Gauquelin; J Verbeeck; H Hilgenkamp; A Brinkman; J Aarts

doi:10.1038/s41598-021-89767-3

Gate-tuned anomalous Hall effect driven by Rashba splitting in intermixed LaAlO₃/GdTiO₃/SrTiO₃

Sci Rep. 2021 May 21;11(1):10726. doi: 10.1038/s41598-021-89767-3.

Authors

N Lebedev^#¹, M Stehno^#², A Rana^{3

4}, P Reith⁴, N Gauquelin⁵, J Verbeeck⁵, H Hilgenkamp⁴, A Brinkman⁴, J Aarts⁶

Affiliations

¹ Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA, Leiden, The Netherlands.
² Physikalisches Institut (EP 3), Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
³ Center for Advanced Materials and Devices, BML Munjal University (Hero Group), Gurgaon, 122413, India.
⁴ MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
⁵ Electron Microscopy for Materials Science, University of Antwerp, Campus Groenenborger Groenenborgerlaan 171, 2020, Antwerpen, Belgium.
⁶ Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA, Leiden, The Netherlands. aarts@physics.leidenuniv.nl.

^# Contributed equally.

Abstract

The Anomalous Hall Effect (AHE) is an important quantity in determining the properties and understanding the behaviour of the two-dimensional electron system forming at the interface of SrTiO₃-based oxide heterostructures. The occurrence of AHE is often interpreted as a signature of ferromagnetism, but it is becoming more and more clear that also paramagnets may contribute to AHE. We studied the influence of magnetic ions by measuring intermixed LaAlO₃/GdTiO₃/SrTiO₃ at temperatures below 10 K. We find that, as function of gate voltage, the system undergoes a Lifshitz transition while at the same time an onset of AHE is observed. However, we do not observe clear signs of ferromagnetism. We argue the AHE to be due to the change in Rashba spin-orbit coupling at the Lifshitz transition and conclude that also paramagnetic moments which are easily polarizable at low temperatures and high magnetic fields lead to the presence of AHE, which needs to be taken into account when extracting carrier densities and mobilities.