Extra Seminar - Würzburg ToCoTronics Colloquium

Magnetically doped topological insulators such as V-doped (BixSb1-x)2Te3 (V- BST) exhibit the quantum anomalous Hall (QAH) effect, characterized by the emergence of a single chiral edge state propagating in a direction set by the magnetization. Thanks to quantized edge state transport in the absence of an external magnetic field, QAH systems offer exciting opportunities to study the interplay between edge state transport and magnetism at domain walls, as well as to couple chiral edge states to superconductors, for instance to generate flying Majorana states.

Here, I report on dynamical transport measurements in MBE-grown V-BST. Using short current pulses in combination with low-frequency measurements, we first investigate the dynamics of current-induced magnetization switching [1]. The reversal is shown to be thermally activated and driven by Joule heating. Second, we study high-frequency transport in the GHz regime and observe plasmon propagation over long distances [2,3]. Their velocity and attenuation indicate interactions with charge puddles as a primary source of dissipation.

Overall, QAH edge states provide a promising platform for coherent electronic transport in chiral channels. I conclude by discussing current results and future research directions.

[1] A. Rupp et al., arXiv:2507.19665, accepted in PRL
[2] T. Röper et al., PRB 110, L161403 (2024)
[3] T. Röper et al., PRB 112, L201301 (2025)