Andrea Young

University of California

Superconductivity and magnetism in ultra-clean rhombohedral multilayer graphene

The electronic band structure of rhombohedral multilayer graphene hosts van Hove singularities at which the single particle density of states diverges.  I will discuss experiments in which we use electrostatic gates to tune the chemical potential through these exceptional points.  As the density of states increases, interparticle interactions lift the resulting massive degeneracy, giving rise to a cascade of correlated electron phases including both magnets and superconductors that can be tuned, in situ, using small changes in carrier density or applied perpendicular electric field.  I will describe how the exceptional tunability and near absence of disorder in these systems allows in-depth probes of the nature and origin of the superconducting states, as well as enabling new device geometries in which superconductivity can be interfaced with chiral edge states within the same two dimensional electron system using only the electric field effect.