Twisted Kagome Bilayers: High-Order Van Hove Singularities, Sublattice Interference, Magic Angles, and Possible Topology

Abstract

We develop a low-energy continuum model to describe the moiré physics of heterostructures, which is a generalization of the celebrated Bistritzer-MacDonald (BM) method [R. Bistritzer and A. H. MacDonald, Proc. Natl. Acad. Sci. U.S.A. 108, 12233 (2011)]. We take as an example the moiré physics of electrons in twisted bilayer kagome metals near 1/3 filling where monolayer Dirac cones lie. We demonstrate the emergence of magic angles where significant local band flattening occurs as a high-order Van Hove singularity appears and find a momentum-dependent anti-unitary particle-hole symmetry potentially enabling stable topology. We, furthermore, show that while sublattice interference effects are present, their role is not as prominent as in monolayer kagome.

Main text: 7 pages, 3 figures. Supplemental Material: 20 pages, 7 figures