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Surface‐Driven Evolution of the Anomalous Hall Effect in Magnetic Topological Insulator MnBi 2 Te 4 Thin Films
Author(s) -
Mazza Alessandro R.,
Lapano Jason,
MeyerIII Harry M.,
Nelson Christopher T.,
Smith Tyler,
Pai YunYi,
Noordhoek Kyle,
Lawrie Benjamin J.,
Charlton Timothy R.,
Moore Robert G.,
Ward T. Zac,
Du MaoHua,
Eres Gyula,
Brahlek Matthew
Publication year - 2022
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202202234
Subject(s) - topological insulator , spintronics , magnetism , materials science , condensed matter physics , quantum anomalous hall effect , hall effect , stoichiometry , surface states , surface (topology) , topology (electrical circuits) , nanotechnology , quantum hall effect , magnetic field , ferromagnetism , physics , quantum mechanics , chemistry , geometry , mathematics , organic chemistry , combinatorics
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 MnBi 2 Te 4 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 MnBi 2 Te 4 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.