1. Quantitative determination of twist angle and strain in Van der Waals moir\'e superlattices
- Author
-
Tran, Steven J., Uslu, Jan-Lucas, Pendharkar, Mihir, Finney, Joe, Sharpe, Aaron L., Hocking, Marisa, Bittner, Nathan J., Watanabe, Kenji, Taniguchi, Takashi, Kastner, Marc A., Mannix, Andrew J., and Goldhaber-Gordon, David
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Scanning probe techniques are popular, non-destructive ways to visualize the real space structure of Van der Waals moir\'es. The high lateral spatial resolution provided by these techniques enables extracting the moir\'e lattice vectors from a scanning probe image. We have found that the extracted values, while precise, are not necessarily accurate. Scan-to-scan variations in the behavior of the piezos which drive the scanning probe, and thermally-driven slow relative drift between probe and sample, produce systematic errors in the extraction of lattice vectors. In this Letter, we identify the errors and provide a protocol to correct for them. Applying this protocol to an ensemble of ten successive scans of near-magic-angle twisted bilayer graphene, we are able to reduce our errors in extracting lattice vectors to less than 1%. This translates to extracting twist angles with a statistical uncertainty less than 0.001{\deg} and uniaxial heterostrain with uncertainty on the order of 0.002%., Comment: 20 pages including supplementary material and 3 main figures
- Published
- 2024