고려대학교 물리학과

Twisted bilayer graphene is gaining a renewed interest after the experimental observation of flat band superconductivity associated at appropriate twist angles and pressure tunable interlayer coupling. In this presentation I will introduce research efforts from our group to obtain accurate electronic structures of twisted bilayer and multilayer graphene that uses input from ab initio calculations and experimental data, in search of optimum twist angles and interlayer potential differences for finding isolated nearly flat bands where Coulomb interactions play a dominant role. Our studies indicate that the conditions for band narrowing and isolation can be expected in a variety of twisted graphene systems and they are achieved more easily when the constituent materials have a band gap, which in rhombohedrally stacked multilayers can be produced by a perpendicular electric field.