Designer electronicstates in van der Waals heterostructures

Abstract: The ability to create arbitrary stackingconfigurations of layered two-dimensional materials has opened the way to thecreation of designer band structures. Twisted bilayer graphene and graphene on hexagonal boron nitride are twoof the simplest examples of such a van der Waals heterostructure where theelectronic properties of the composite material can be fundamentally differentfrom either individual material.   Thesevan der Waals heterostructures can be formed using a wide variety of layeredmaterials including transition metal dichalcogenides, graphene and topologicalinsulators.  The lattice mismatch andtwist angle between layers in the heterostructure produces a moiré patternwhich affects its electronic properties. This talk will mostly focus on creating novel electronic states bycontrolling the twist angle and breaking inversion symmetry.  In small twist angle bilayer graphene ortransition metal dichalcogenides, the long-wavelength moiré pattern leads tothe creation of flat bands and a wide range of correlated electronicstates.  In this talk, I will discuss ourfabrication of these heterostructures and measurements using scanning probemicroscopy.