Emerging Ferroelectric Domains: Stacking and Rotational Landscape of MoS2 Moire Bilayers

The structures and properties of moire patterns in twisted bilayers of two-dimensional (2D) materials are known to depend sensitively on twist angle, yet their dependence on stacking order remains comparatively underexplored. In this study, we use molecular dynamics simulations to systematically investigate the combined effects of stacking order and rotation in MoS2 bilayers. Beginning from five well-established high-symmetry bilayer stackings, we apply twist angles between 1 and 120 to the top layer, revealing a variety of relaxed moire structures. Our results show that the initial stacking significantly influences the moire domain configurations that emerge at a given twist angle. While all five stacking orders are metastable without twist, they form two moire-equivalent classes- AA/AB and AA',A'B,AB', i.e., for a given twist angle, structures within each class relax to the same moire configuration. Specifically, initial AA and AB stackings give rise to triangular ferroelectric domains near 0+/-3, while AA', A'B, and AB' stackings produce triangular ferroelectric domains near 60+/-3. At precisely 60 and 120 twists, the bilayers relax to into pure high-symmetry stackings, highlighting the rotational relationships between these configurations and explaining the shift of 60 in the ferroelectric rotational range. These findings demonstrate the critical role of stacking order in governing the rich moire landscapes accessible in twistronic systems.