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arXiv · 2412.20129

Altermagnetism Induced Topological Phase Transitions in Kane-Mele Model

Zhengtian Li·Zeyu Li·Zhenhua Qiao
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Abstract

We theoretically demonstrate that Chern number tunable quantum anomalous Hall effect (QAHE) and second-order topological insulators can be induced in the two-dimensional $\mathbb{Z}_2$ topological insulator (TI), i.e., Kane-Mele model, by applying $d$-wave altermagnetism. When the N\'eel vector of altermagentism lies in the $x-y$ plane, the $\mathbb{Z}_2$ TI is broken and driven into a second-order topological insulator phase, exhibiting the representative corner states at nanoflakes. When the intrinsic Rashba spin-orbit coupling is further included, the second-order TI is further driven into the QAHE phase with various Chern numbers (e.g., $\mathcal{C}=\pm1$ or $\pm3$). When the N\'eel vector is along $z$ direction, the intrinsic Rashba spin-orbit coupling is necessary to break the mirror symmetry to allow a sequential emergence of second-order TI and QAHE along with the increase of altermagentism strength. We also observe the QAHE with mixed-chirality, i.e., there exist counter-propagating edge modes but net chiral current at the ribbon boundary. Our work shows that altermagnetism can play a crucial role in exploring a rich variety of topological phases, just like its counterparts of ferromagnetism and antiferromagnetism.

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Zhengtian Li, Zeyu Li, Zhenhua Qiao. 2024-12-28. Altermagnetism Induced Topological Phase Transitions in Kane-Mele Model. https://doi.org/10.1103/physrevb.111.155303

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