biostudies-literatureZhang HFundamental Research Funds for the Central UniversitiesDivision of Materials Sciences and EngineeringNational Natural Science Foundation of ChinaNational Key Research and Development Program of ChinaNational Science Foundation4689-4695https://www.ebi.ac.uk/biostudies/studies/S-EPMC11951140biostudies-literatureUnknown25(12)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 antiferromagnetic FeSn films using low-temperature scanning tunneling microscopy and spectroscopy. Near the single Sn vacancy, anisotropic quasiparticle interference patterns are observed in the differential conductance d<i>I</i>/d<i>V</i> maps, breaking the 6-fold rotational symmetry of the Kagome layer. Furthermore, the Sn vacancy defects induce bound states that exhibit anomalous Zeeman shift under an out-of-plane magnetic field, where the energy of the bound states moves linearly toward 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 2-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.Nano lettersAnisotropic Response of Defect Bound States to the Magnetic Field in Epitaxial FeSn Films.PMC11951140DUT24LK007DUT22LAB104EFMA-1741673DUT24RC(3)015DE-SC0017632DUT22ZD103123042102023YFB3809600Weinert MZhang HWang ZLi LfalseAnisotropic Response of Defect Bound States to the Magnetic Field in Epitaxial FeSn Films.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 antiferromagnetic FeSn films using low-temperature scanning tunneling microscopy and spectroscopy. Near the single Sn vacancy, anisotropic quasiparticle interference patterns are observed in the differential conductance d<i>I</i>/d<i>V</i> maps, breaking the 6-fold rotational symmetry of the Kagome layer. Furthermore, the Sn vacancy defects induce bound states that exhibit anomalous Zeeman shift under an out-of-plane magnetic field, where the energy of the bound states moves linearly toward 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 2-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.2025-01-01T00:00:00Z2025 Mar2025-07-05T03:04:25.245Z2025-07-05T03:04:25.245ZS-EPMC119511404008224710.1021/acs.nanolett.4c05337