Moiré Patterns in van der Waals Heterojunctions

Allan MacDonald, University of Texas at Austin
Location: CB2 206, 4:00-5:00pm
Friday, November 18th, 2016

Abstract: According to Wikipedia a moiré pattern (/mwɑːrˈeɪ/; French: [mwaˈʁe]) is a large scale interference pattern that is produced when an opaque regular pattern with transparent gaps is overlaid on another similar pattern. A moiré pattern appears only when the regular patterns are rotated by a small twist angle relative to each other or have different, but similar pitches. Moiré patterns are ubiquitous in van der Waals heterojunctions because the layered two-dimensional crystals tend not to lattice match. Moiré patterns are common, influence all physical properties, and can be controlled by varying relative orientation. I will discuss some examples of new physics that can be realized using moiré patterns formed by graphene on hexagonal boron-nitride, by graphene on graphene, and by transition metal dichalcogenides bilayers.