Matthew Yankowitz

(Columbia)


Dynamic band structure tuning of 2D van der Waals heterostructures with pressure



Heterostructures assembled from various atomically-thin van der Waals (vdW) materials offer a highly flexible platform for realizing novel electronic devices, as emergent electronic properties not found in any of the constituent materials alone often arise due to interfacial electronic interactions. While significant effort has previously focused on controlling the properties of these devices through the ordering of the vdW materials in the heterostructure and their relative rotation, so far very little attention has been paid to controlling the strength of the interlayer electronic interactions directly. By applying hydrostatic pressure to vdW heterostructure devices, we find that we are able to directly tune the strength of these interactions by changing the interlayer spacing of the vdW crystals. Notably, in the case of graphene rotationally aligned with boron nitride, a long-wavelength moire superlattice emerges which opens a gap in the graphene band structure. We find that we are able to nearly double the size of the graphene band gap by tuning the strength of the interaction-induced moire potential with pressure.