Complex Strain Scapes in Reconstructed Transition-Metal Dichalcogenide Moiré Superlattices.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37022987.
- Also identified by DOI 10.1021/acsnano.3c00609 and PMC identifier 10134736.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We investigate the intrinsic strain associated with the coupling of twisted MoS<sub>2</sub>/MoSe<sub>2</sub> heterobilayers by combining experiments and molecular dynamics simulations. Our study reveals that small twist angles (between 0 and 2°) give rise to considerable atomic reconstructions, large moiré periodicities, and high levels of local strain (with an average value of ∼1%). Moreover, the formation of moiré superlattices is assisted by specific reconstructions of stacking domains. This process leads to a complex strain distribution characterized by a combined deformation state of uniaxial, biaxial, and shear components. Lattice reconstruction is hindered with larger twist angles (>10°) that produce moiré patterns of small periodicity and negligible strains. Polarization-dependent Raman experiments also evidence the presence of an intricate strain distribution in heterobilayers with near-0° twist angles through the splitting of the E<sub>2g</sub><sup>1</sup> mode of the top (MoS<sub>2</sub>) layer due to atomic reconstruction. Detailed analyses of moiré patterns measured by AFM unveil varying degrees of anisotropy in the moiré superlattices due to the heterostrain induced during the stacking of monolayers.