Creating and imaging topological states in two-dimensional materials
Abstract
The ability to create arbitrary structures by stacking two dimensional materials holds tremendous promise for future applications in electronics and optics. By proper choice of materials, arbitrary designer bandstructures can be created in these van der Waals heterostructures. This project will create and probe topologically protected states in these heterostructures. The heterostructures will be fabricated using layer-by-layer assembly of two-dimensional materials. Through a suitable choice of the component materials and their relative orientations, we will break symmetries of the crystals such as sublattice, valley, time-reversal, etc. to enable topologically protected states. These states will carry currents that are immune to scattering. To probe these broken symmetries, measurement techniques that are sensitive on the atomic scale are needed. Using spatially and time-resolved techniques, we will investigate the electronic and optical properties of these topological states. In particular we will investigate the following items: (1) Controllably create and image zero-line modes in twisted bilayer graphene which can carry a dissipationless current. (2) Realize the quantum anomalous Hall effect in graphene coupled to a 2D ferromagnet. (3) Probe topological excitons in coupled transition metal dichalcogenide bilayer heterostructures. These measurements will serve as a basis for understanding the unique topological properties that can emerge in van der Waals heterostructures. The understanding of these novel heterostructures will open new nanodevice applications of interest to the Army.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010215
Entities
People
- Brian J LeRoy
Organizations
- Army Contracting Command
- United States Army
- University of Arizona