Twisted Kagome Bilayers: Higher-Order Magic Angles, Topological Flat Bands, and Sublattice Interference

Abstract

We develop a low-energy continuum model to describe the moir\'{e} 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 moir\'{e} physics of electrons in twisted bilayer kagom\'{e} (TBK) metals near $1/3$ filling where monolayer Dirac cones lie. We demonstrate the emergence of higher-order magic angles where significant local band flattening occurs as a high-order Van Hove singularity emerges and show how twisting alone can induce non-trivial topology. We, furthermore, show that while sublattice interference effects are present, their role is not as prominent as in monolayer kagome.