Light‐Induced Quantum Anomalous Hall Effect on the 2D Surfaces of 3D Topological Insulators
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advs.202101508.pdf
Description
Published version
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934.26 KB
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Adobe PDF
Checksum (MD5)
6e372adbe463005c3d2b7f47e7cbb909
Author(s)
Xu, Haowei
Zhou, Jian
Li, Ju
Date Issued
September 2021
Journal
Advanced Science
Publisher
Wiley
Version
Final published version
Abstract
Quantum anomalous Hall (QAH) effect generates quantized electric charge Hall conductance without external magnetic field. It requires both nontrivial band topology and time-reversal symmetry (TRS) breaking. In most cases, one can break the TRS of time-reversal invariant topological materials to yield QAH effect, which is essentially a topological phase transition. However, conventional topological phase transition induced by external field/stimulus usually needs a route along which the bandgap closes and reopens. Hence, the transition occurs only when the magnitude of field/stimulus is larger than a critical value. In this work the authors propose that using gapless systems, the transition can happen at an arbitrarily weak (but finite) external field strength. For such an unconventional topological phase transition, the bandgap closing is guaranteed by bulk-edge correspondence and symmetries, while the bandgap reopening is induced by external fields. This concept is demonstrated on the 2D surface states of 3D topological insulators like Bi2 Se3 , which become 2D QAH insulators once a circularly polarized light is turned on, according to the Floquet time crystal theory. The sign of quantized Chern number can be controlled via the chirality of the light. This provides a convenient and dynamic approach to trigger topological phase transitions and create QAH insulators.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1002/advs.202101508
