Improving the understanding of moiré spatial structure and electronic transport properties

Over the last half decade, electrical transport studies of Van der Waals moiré superlattices have revealed rich correlated and topological phenomena. However, the actual spatial structure of the superlattice which give rise to the electronic properties are still not well understood as electrical transport averages over local inhomogeneities between contact pairs. Scanning probe techniques are popular, nondestructive ways to directly visualize the real space structure of moirés. In this talk I will describe progress in using the recently developed torsional force microscopy, an atomic force microscope (AFM) based technique, to provide complimentary spatial structure information to electrical transport. I will highlight challenges in extracting quantitative structural information from AFM images and describe a protocol which overcomes these challenges to get accurate determination of local twist angle and strain. If time permits, I will show preliminary results of electrical transport through regions of a twisted bilayer graphene superlattice with pre-characterized spatial structure.