Regensburg 2022 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: Poster
DS 20.23: Poster
Wednesday, September 7, 2022, 16:00–18:00, P3
Chern number control in quantum anomalous Hall insulators by external fields — •Yuriko Baba1, 2, Francisco Domínguez-Adame1, and Rafael A. Molina-Ferández2 — 1GISC, Departamento de Física de Materiales, Universidad Complutense, E--28040 Madrid, Spain — 2Instituto de Estructura de la Materia, IEM-CSIC, E--28006 Madrid, Spain
Topological magnetic insulators have been discovered as a new platform for observing Quantum Anomalous Hall states with high Chern number C. In three-dimensional structures of stacking layers of magnetically doped and undoped topological insulators of Bi2(Se,Te)3, the number of chiral edge channels can be controlled by the width and number of layers and by the doping concentration. This has been recently measured by Zhao et al. [1] in Cr doped samples, showing this feature up to C = 5.
In this theoretical work, we explore the possibilities of tuning the chiral channels of the aforementioned materials in the presence of electric fields in multilayered structures. The external field tunes the Chern number and changes the number of topological channels dynamically without the need of replacing the sample to modify the Chern number. The tuneability has a remarkable impact on the transport properties of pristine and disordered samples.
[1] Zhao, Y. F. et al., Nature, 588 (2020) 419