Novel Moiré Pattern of a New Two-Dimensional Lattice

We propose a new type of two-dimensional lattice structure, which hosts quadratic band touching in its bilayer form, resulting in intriguing strongly correlated physics such as superconductivity with high critical temperature. Further, multiple isolated flat bands near the Fermi level are induced by the Moiré pattern of its twisted bilayer structure. These isolated flat bands are topological and host high-spin Chern numbers: we demonstrate this formally and confirm our findings via numerical calculations. Non-trivial topology of flat bands indicates the presence of a significant quantum weight, implying a substantial superfluid weight when a BCS-type pairing potential is added. The number of flat bands and their superfluid weight here are greater than in the case of twisted bilayer graphene. Our study suggest a new platform for exploring flat-band physics via Moiré engineering. Work supported by the NSF.