Published August 9, 2024
| Version v1
Journal article
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Distinguishing surface and bulk electromagnetism via their dynamics in an intrinsic magnetic topological insulator
Creators
- 1. University of Chicago
- 2. University of Florida
- 3. Pennsylvania State University
- 4. Weizmann Institute of Science
Description
The indirect exchange interaction between local magnetic moments via surface electrons has been long predicted to bolster the surface ferromagnetism in magnetic topological insulators (MTIs), which facilitates the quantum anomalous Hall effect. This unconventional effect is critical to determining the operating temperatures of future topotronic devices. However, the experimental confirmation of this mechanism remains elusive, especially in intrinsic MTIs. Here, we combine time-resolved photoemission spectroscopy with time-resolved magneto-optical Kerr effect measurements to elucidate the unique electromagnetism at the surface of an intrinsic MTI MnBi2Te4. Theoretical modeling based on 2D Ruderman-Kittel-Kasuya-Yosida interactions captures the initial quenching of a surface-rooted exchange gap within a factor of two but overestimates the bulk demagnetization by one order of magnitude. This mechanism directly explains the sizable gap in the quasi-2D electronic state and the nonzero residual magnetization in even-layer MnBi2Te4. Furthermore, it leads to efficient light-induced demagnetization comparable to state-of-the-art magnetophotonic crystals, promising an effective manipulation of magnetism and topological orders for future topotronics.
Data availability
All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.Files
sciadv.adn5696.pdf
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(2.9 MB)
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Article md5:017c81c4f460cff2f0d84e647812b059 |
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Supplementary materials md5:a9eaaf538c3744b56f66f38cf9345162 |
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Additional details
Identifiers
- DOI
- 10.1126/sciadv.adn5696
- Other
- oai:uchicago.tind.io:13134
Funding
- U.S. Department of Energy
- DE-SC0022960
- U.S. Department of Energy
- DE-SC0022983
- Pennsylvania State University
- DMR 2039351