IRG1 of the Columbia MRSEC seeks to understand the behavior of van der Waals heterostructures created by assembly of atomically thin layered materials. One important question in this effort is how the relative orientation between the layers affects multiple properties.
In the last year, MRSEC fellow Rebeca Ribeiro-Palau and Bridge-to-PhD fellow Kursti DeLello have developed a technique to change the orientation between layers in a heterostructure using an atomic force micrsocope (AFM). This is done by pushing the top layer of the structure with the AFM tip in contact mode. It allows extremely precise control of angle, to within 0.1 degrees.
In the first studies using this technique, the team has examined the change of electronic behavior of graphene/BN structures due to the control of a Moire’ superlattice and found a correlation of this with a high friction regime between the layers. This work sets the stage for a broad experimental and theoretical program to study angle-dependent phenomena in heterostructures