Visualizing symmetry-breaking electronic orders in epitaxial Kagome magnet FeSn films.

Zhang, Huimin; Oli, Basu Dev; Zou, Qiang; Guo, Xu; Wang, Zhengfei; Li, Lian · Nat Commun · 2023

basic_science · Level V

Where this comes from

Abstract

Kagome lattice hosts a plethora of quantum states arising from the interplay of topology, spin-orbit coupling, and electron correlations. Here, we report symmetry-breaking electronic orders tunable by an applied magnetic field in a model Kagome magnet FeSn consisting of alternating stacks of two-dimensional Fe<sub>3</sub>Sn Kagome and Sn<sub>2</sub> honeycomb layers. On the Fe<sub>3</sub>Sn layer terminated FeSn thin films epitaxially grown on SrTiO<sub>3</sub>(111) substrates, we observe trimerization of the Kagome lattice using scanning tunneling microscopy/spectroscopy, breaking its six-fold rotational symmetry while preserving the translational symmetry. Such a trimerized Kagome lattice shows an energy-dependent contrast reversal in dI/dV maps, which is significantly enhanced by bound states induced by Sn vacancy defects. This trimerized Kagome lattice also exhibits stripe modulations that are energy-dependent and tunable by an applied in-plane magnetic field, indicating symmetry-breaking nematicity from the entangled magnetic and charge degrees of freedom in antiferromagnet FeSn.