Occurring monthly during the academic year, the 2DCC Webinars present new technical scientific news from within the 2DCC facility and the broader scientific community, as well as, broader topics such as science related to diversity. The webinars are free with an online registration. The slides with voice-over for the 2016 webinars, 2017 webinars, and 2018 webinars are available by following the links in the left menu. Information regarding the next scheduled webinar is listed below.
DATE: Tuesday, November 5, 2019
TIME: 12:00 pm - 1:00 pm Eastern
Title: "Designer electronic states in van der Waals heterostructures"
Dr. Brian LeRoy
Professor of Physics
University of Arizona
Summary: The ability to create arbitrary stacking configurations of layered two-dimensional materials has opened the way to the creation of designer band structures. Twisted bilayer graphene and graphene on hexagonal boron nitride (hBN) are two of the simplest examples of such a van der Waals heterostructure where the electronic properties of the composite material can be fundamentally different from either individual material. These van der Waals heterostructures can be formed using a wide variety of layered materials including transition metal dichalcogenides, graphene and topological insulators. This talk will mostly focus on creating novel electronic states by controlling the twist angle and breaking inversion symmetry. The lattice mismatch and twist angle between layers in the heterostructure produces a moiré pattern which affects its electronic properties. For graphene on hBN, the moiré pattern creates a new set of superlattice Dirac points. In small twist angle bilayer graphene or transition metal dichalcogenides, the long-wavelength moiré pattern leads to the creation of flat bands and a wide range of correlated electronic states. In this talk, I will discuss our fabrication of these heterostructures and measurements using scanning probe microscopy.