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arXiv · 2503.08072

Anisotropic response of defect bound states to magnetic field in epitaxial FeSn films

Huimin Zhang·Zhengfei Wang·Michael Weinert·Lian Li
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Abstract

Crystal defects, whether intrinsic or engineered, drive many fundamental phenomena and novel functionalities of quantum materials. Here, we report symmetry-breaking phenomena induced by Sn-vacancy defects on the surface of epitaxial Kagome antiferromagnet FeSn films using low-temperature scanning tunneling microscopy and spectroscopy. Near the Sn-vacancy defects, anisotropic quasiparticle interference patterns are observed in the differential conductance dI/dV maps, indicating two-fold electronic states that break the 6-fold rotational symmetry of the Kagome layer. Furthermore, the Sn-vacancy defects induce bound states that exhibit anomalous Zeeman shifts under an out-of-plane magnetic field, where their energy shifts linearly towards higher energy independent of the direction of the magnetic field. Under an in-plane magnetic field, the shift of the bound state energy also shows a two-fold oscillating behavior as a function of the azimuth angle. These findings demonstrate defect-enabled new functionalities in Kagome antiferromagnets for potential applications in nanoscale spintronic devices.

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Huimin Zhang, Zhengfei Wang, Michael Weinert, Lian Li. 2025-03-11. Anisotropic response of defect bound states to magnetic field in epitaxial FeSn films. https://doi.org/10.1021/acs.nanolett.4c05337

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