Quantum materials whose atoms are arranged on a lattice of corner-sharing triangles, i.e., the kagome lattice, have recently emerged as a captivating platform for investigating exotic correlated and topological electronic phenomena. Here, we combine ultra-low temperature angle-resolved photoemission spectroscopy (ARPES) with scanning tunneling microscopy and density functional theory calculations to reveal the fascinating electronic structure of the bilayer-distorted kagome material LnTi3Bi4, where Ln stands for Nd and Yb. Distinct from other kagome materials, LnTi3Bi4 exhibits two-fold, rather than six-fold, symmetries, stemming from the distorted kagome lattice, which leads to a unique electronic structure. Combining experiment and theory we map out the electronic structure and discover double flat bands as well as multiple van Hove singularities (VHSs), with one VHS exhibiting higher-order characteristics near the Fermi level. Notably, in the magnetic version NdTi3Bi4, the ultra-low base temperature ARPES measurements unveil an unconventional band splitting in the band dispersions which is induced by the ferromagnetic ordering. These findings reveal the potential of bilayer-distorted kagome metals LnTi3Bi4 as a promising platform for exploring novel emergent phases of matter at the intersection of strong correlation and magnetism.
@article{arxiv.2311.07747,
title = {Magnetic-coupled electronic landscape in bilayer-distorted titanium-based kagome metals},
author = {Yong Hu and Congcong Le and Long Chen and Hanbin Deng and Ying Zhou and Nicholas C. Plumb and Milan Radovic and Ronny Thomale and Andreas P. Schnyder and Jia-Xin Yin and Gang Wang and Xianxin Wu and Ming Shi},
journal= {arXiv preprint arXiv:2311.07747},
year = {2024}
}