Strain-Induced Moiré Polarization Vortices in Twisted-Multilayer WSe₂

Moiré superlattices in 2D van der Waals (vdW) materials enable the engineering of local polarization textures and electrostatic potential landscapes. While polarization vortices are demonstrated in bilayer transition metal dichalcogenides (TMDs), their formation mechanisms in multilayers remain unclear. Here, it is shown that in multi-twisted small-angle multilayer WSe₂, nanoscale strain fields, not twist alone, govern the emergence, and stability of polarization vortices. Using 4D scanning transmission electron microscopy (4D-STEM) with an electron microscope pixel array detector (EMPAD), local electrostatic potential variations and strain distributions are spatially resolved with nanometer precision. It is found that vortex-like polarization textures emerge exclusively in regions with significant nanoscale strain, revealing a direct interplay between lattice reconstruction and Moiré-induced polarization textures in twisted multilayers. The findings establish strain as a key tuning parameter for Moiré-induced polarization control, providing new pathways for strain-engineered 2D vdW materials, chiral dipole textures, and next-generation low-power electronic and optoelectronic devices.