Visualizing ultrafast lattice dynamics at 2D van der Waals interfaces using femtosecond electron diffraction

Two-dimensional semiconductors prepared from van der Waals crystals of transition metal dichalcogenides are a burgeoning area of research with unique layer-dependent optoelectronic properties. Atomically precise junctions can be assembled by mechanically placing two such semiconductor monolayers on top of each other without any constraints of epitaxy or covalent bonding. In this talk I will describe our efforts to uncover the role of layer-hybridized electronic states as a powerful route to control ultrafast energy transport across such 2D heterojunctions by using a combination of ultrafast electron diffraction thermometry and first-principles calculations. Our experiments and theory present a new understanding of the microscopic origins of ultrafast charge and energy transport across two dimensional heterostructures.