Abstract
Engineering electronic band structures of atomically thin 2D materials using exotic periodic potentials has provided a profound platform to explore new physics in solid state systems. Many new discoveries have been made under different types of superlattice potential, which include but not limited to the observations of the Hofstadter’s butterfly in graphene-hexagonal boron nitride (hBN) moiré superlattices, the unconventional superconductivity in magic-angle twisted bilayer graphene as well as the anisotropic band flattening of graphene under one-dimensional (1D) superlattice potential. This mainly comes from the fact that the superlattice structure induces additional periodicity in the pristine lattice structure of 2D materials which gives rise to the creation of new set of minibands in the momentum space. Here, we will discuss our ongoing efforts and progresses to build new types of superlattice structures that can reveal new physics. First, we will discuss our new idea(s) to construct 1d superlattice potential in graphene with a periodicity of only a few nanometer. We believe that such an ultrashort periodic superlattice can induce a few potential barriers across the Fermi wavelength of an electron at a wide range of density which can give rise to new types of electronic bands. Second, by creating an insulating substrate that forms moiré superlattice potential landscape, we will explore the possibilities of engineering band structures of various 2D materials whose crystal structures are not so favorable to make moiré superlattice structures. We will first demonstrate the technique by observing satellite Dirac peaks in graphene on twisted hBN substrate. We expect that these two techniques can provide routes to explore new types of electronic bands in a large family of 2D materials.
Anyone interested is welcome to attend.