Abstract
Understanding the effects of the interfacial modification to the functional properties of magnetic topological insulator thin films is crucial for developing novel technological applications from spintronics to quantum computing. Here, a large electronic and magnetic response is reported to be induced in the intrinsic magnetic topological insulator MnBi2Te4 by controlling the propagation of surface oxidation. It is shown that the formation of the surface oxide layer is confined to the top 1–2 unit cells but drives large changes in the overall magnetic response. Specifically, a dramatic reversal of the sign of the anomalous Hall effect is observed to be driven by finite thickness magnetism, which indicates that the film splits into distinct magnetic layers each with a unique electronic signature. These data reveal a delicate dependence of the overall magnetic and electronic response of MnBi2Te4 on the stoichiometry of the top layers. This study suggests that perturbations resulting from surface oxidation may play a non-trivial role in the stabilization of the quantum anomalous Hall effect in this system and that understanding targeted modifications to the surface may open new routes for engineering novel topological and magnetic responses in this fascinating material.
Original language | English |
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Article number | 2202234 |
Journal | Advanced Functional Materials |
Volume | 32 |
Issue number | 28 |
DOIs | |
State | Published - Jul 11 2022 |
Funding
This work was supported by the U. S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division (growth, neutron, transport, electron microscopy, spectroscopy, and density functional calculations), and the National Quantum Information Science Research Centers, Quantum Science Center (structure). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The author's wish to thank Jiaqiang Yan and Andrew F. May for insightful discussions and Ryan Comes and Patrick Gemperline for insight into the XPS measurements. This work was supported by the U. S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division (growth, neutron, transport, electron microscopy, spectroscopy, and density functional calculations), and the National Quantum Information Science Research Centers, Quantum Science Center (structure). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The author's wish to thank Jiaqiang Yan and Andrew F. May for insightful discussions and Ryan Comes and Patrick Gemperline for insight into the XPS measurements.
Keywords
- MnBi Te
- intrinsic magnetic topological insulators
- molecular beam epitaxy
- quantum anomalous Hall
- quantum materials
- topological materials