Moire flat bands of twisted few-layer graphite

We report that the twisted few layer graphite (tFL-graphite) is a new family of moire heterostructures (MHSs), which has richer and highly tunable moire flat band structures entirely distinct from all the known MHSs. A tFL-graphite is composed of two few-layer graphite (Bernal stacked multilayer graphene), which are stacked on each other with a small twisted angle. The moire band structure of the tFL-graphite strongly depends on the layer number of its composed two van der Waals layers. Near the magic angle, a tFL-graphite always has two nearly flat bands coexisting with a few pairs of narrowed dispersive (parabolic or linear) bands at the Fermi level, thus, enhances the DOS at E-F. This coexistence property may also enhance the possible superconductivity as been demonstrated in other multiband superconductivity systems. Therefore, we expect strong multiband correlation effects in tFL-graphite. Meanwhile, a proper perpendicular electric field can induce several isolated nearly flat bands with nonzero valley Chern number in some simple tFL-graphites, indicating that tFL-graphite is also a novel topological flat band system.

Automated summary

We report a new family of twisted few layer graphite, which has distinct moire flat band structures that can be highly tuned. The moire band structure strongly depends on the layer number of the graphite, and near the magic angle, it exhibits two nearly flat bands coexisting with dispersive bands. This property enhances the possible superconductivity and also indicates that it is a novel topological flat band system.