Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 28: Topological Insulators (joint session MA/KFM)

KFM 28.7: Vortrag

Donnerstag, 8. September 2022, 16:45–17:00, H37

Current-induced breakdown of the quantum anomalous Hall effect — •Gertjan Lippertz1,2, Andrea Bliesener1, Anjana Uday1, Lino M.C. Pereira2, Alexey Taskin1, and Yoichi Ando11University of Cologne, Cologne, Germany — 2KU Leuven, Leuven, Belgium

The quantum anomalous Hall (QAH) effect is characterised by zero longitudinal resistivity and quantized Hall resistance without the need of an external magnetic field. However, when reducing the device dimensions or increasing the current density, an abrupt breakdown of the dissipationless state occurs. In this talk, the mechanism of breakdown will be adressed, and the electric field created between opposing chiral edge states will be shown to lie at its origin. Electric-field-driven percolation of two-dimensional charge puddles in the gapped surface states of compensated topological-insulator films is proposed as the most likely cause of the breakdown [1].

Moreover, it was recently reported that the interplay between the 1D chiral edge state and the 2D surface state can give rise to nonreciprocity in the longitudinal resistance [2]. In this talk, it will be shown that the onset of 2D conduction due to breakdown is sufficient to create the nonreciprocal effect, allowing for efficient switching between the dissipationless and nonreciprocal transport regime of the QAH state.

[1] G. Lippertz et al., arXiv:2108.02081 (2021)

[2] K. Yasuda et al., Nat. Nanotechnol. 15, 831-835 (2020)

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