Topological Charge Density Wave in Kagome Antiferromagnet

In the field of quantum materials, topological concepts have been successfully applied to predict and discover new phases of matter, such as topological insulators. There is also intense research in the discovery and application of topological superconductors. In this proposal, we aim to apply the concepts of topology to a new family of quantum matter: charge density wave materials. We will focus on the kagome antiferromagnet FeGe. Our previous tunneling microscopy data have revealed the presence of a charge density wave that is strongly coupled to the magnetization of individual kagome layers. Now using angle-resolved photoemission spectroscopy at the LOREA beamline at ALBA, we will explore the topological electronic structure. Utilizing the high-resolution capabilities, we will uncover the gap structure and band folding effects related to the charge order. We will also directly measure the in-gap topological boundary modes on side-cleaved samples. These results will establish FeGe as the first material hosting a topological charge density wave.