Emergent layer stacking arrangements in c-axis confined MoTe₂

The layer stacking order in 2D materials strongly affects functional properties and holds promise for next-generation electronic devices. In bulk, octahedral MoTe₂ possesses two stacking arrangements, the ferroelectric Weyl semimetal T_d phase and the higher-order topological insulator 1T' phase. However, in thin flakes of MoTe₂, it is unclear if the layer stacking follows the T_d, 1T', or an alternative stacking sequence. Here, we use atomic-resolution scanning transmission electron microscopy to directly visualize the MoTe₂ layer stacking. In thin flakes, we observe highly disordered stacking, with nanoscale 1T' and T_d domains, as well as alternative stacking arrangements not found in the bulk. We attribute these findings to intrinsic confinement effects on the MoTe₂ stacking-dependent free energy. Our results are important for the understanding of exotic physics displayed in MoTe₂ flakes. More broadly, this work suggests c-axis confinement as a method to influence layer stacking in other 2D materials.