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arXiv · 2504.10980

Planar Hall effect in ultrathin topological insulator films

Mohammad Shafiei·Milorad V. Milošević
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Abstract

The planar Hall effect (PHE), previously observed in Weyl and Dirac semimetals due to the chiral anomaly, emerges with a different origin in topological insulators (TIs), where in-plane magnetic fields induce resistivity anisotropy. In strictly two-dimensional TIs, PHE is generally suppressed due to the inability of the out-of-plane Berry curvature to couple to the in-plane band velocity of the charge carriers. Here, we demonstrate that in ultrathin TI films, a quasi-two-dimensional system, intersurface tunneling coupling with in-plane magnetization induces electronic anisotropy, enabling a finite PHE. In addition, we reveal that strong in-plane magnetization can stabilize the thickness-dependent quantum anomalous Hall effect, typically associated with out-of-plane magnetization. These insights advance the understanding of magnetic topological phases, paving the way for next-generation spintronic devices and magnetic sensing technologies.

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Mohammad Shafiei, Milorad V. Milošević. 2025-04-15. Planar Hall effect in ultrathin topological insulator films. https://arxiv.org/abs/2504.10980

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