Emergent layer stacking arrangements in c-axis confined MoTe<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37558697.
- Also identified by DOI 10.1038/s41467-023-40528-y and PMC identifier 10412583.
- 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
The layer stacking order in 2D materials strongly affects functional properties and holds promise for next-generation electronic devices. In bulk, octahedral MoTe<sub>2</sub> possesses two stacking arrangements, the ferroelectric Weyl semimetal T<sub>d</sub> phase and the higher-order topological insulator 1T' phase. However, in thin flakes of MoTe<sub>2</sub>, it is unclear if the layer stacking follows the T<sub>d</sub>, 1T', or an alternative stacking sequence. Here, we use atomic-resolution scanning transmission electron microscopy to directly visualize the MoTe<sub>2</sub> layer stacking. In thin flakes, we observe highly disordered stacking, with nanoscale 1T' and T<sub>d</sub> domains, as well as alternative stacking arrangements not found in the bulk. We attribute these findings to intrinsic confinement effects on the MoTe<sub>2</sub> stacking-dependent free energy. Our results are important for the understanding of exotic physics displayed in MoTe<sub>2</sub> flakes. More broadly, this work suggests c-axis confinement as a method to influence layer stacking in other 2D materials.