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Title: Kagome and honeycomb flat bands in moiré graphene
We propose a class of graphene-based moiré systems hosting flat bands on kagome and honeycomb moiré superlattices. These systems are formed by stacking a graphene layer on a 2D substrate with lattice constant approximately sqrt3 times that of graphene. When the moiré potentials are induced by a 2D irreducible corepresentation in the substrate, the model shows a rich phase diagram of low-energy bands including eigenvalue fragile phases as well as kagome and honeycomb flat bands. Spin-orbit coupling in the substrate can lift symmetry-protected degeneracies and create spin Chern bands, and we observe spin Chern numbers up to three. We additionally propose a moiré system formed by stacking two graphene-like layers with similar lattice constants and Fermi energies but with Dirac Fermi velocities of opposite sign. This system exhibits multiple kagome and honeycomb flat bands simultaneously. Both models we propose resemble the hypermagic model of [Scheer et al., Phys. Rev. B 106, 115418 (2022)] and may provide ideal platforms for the realization of strongly correlated topological phases.  more » « less
Award ID(s):
2141966
PAR ID:
10506445
Author(s) / Creator(s):
;
Publisher / Repository:
American Physical Society
Date Published:
Journal Name:
Physical Review B
Volume:
108
Issue:
24
ISSN:
2469-9950
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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