일시: 2021년 11월 30일(화) 오후 5:00
연사: 정재일(서울시립대)
Abstract:
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.