Imaging real-space flat band localization in kagome magnet FeSn

TL;DR

This study visualizes the flat band localization in a magnetic kagome lattice of FeSn using scanning tunneling microscopy, revealing magnetic control over electronic states at the atomic scale.

Contribution

First direct real-space imaging of flat band localization in a magnetic kagome lattice, demonstrating magnetic field manipulation of electronic states.

Findings

Localized flat band state observed at the kagome lattice.

Magnetic field alters the spatial anisotropy of localization.

Results support magnetic tuning of flat band states.

Abstract

Kagome lattices host flat bands due to their frustrated lattice geometry, which leads to destructive quantum interference of electron wave functions. Here, we report imaging of the kagome flat band localization in real-space using scanning tunneling microscopy. We identify both the Fe3Sn kagome lattice layer and the Sn2 honeycomb layer with atomic resolution in kagome antiferromagnet FeSn. On the Fe3Sn lattice, at the flat band energy determined by the angle resolved photoemission spectroscopy, tunneling spectroscopy detects an unusual state localized uniquely at the Fe kagome lattice network. We further show that the vectorial in-plane magnetic field manipulates the spatial anisotropy of the localization state within each kagome unit cell. Our results are consistent with the real-space flat band localization in the magnetic kagome lattice. We further discuss the magnetic tuning of flat band localization under the spin-orbit coupled magnetic kagome lattice model.