Quadruple Moiré Pockets in Lateral Heterobilayers: Programmable Phononic Reconfiguration and Anomalous Second Harmonic Generation

Abstract Moiré‐engineering in 2D transition‐metal dichalcogenides offers access to correlated quantum phenomena. However, simultaneous control over twist‐angle (θ) and material combinations to tune phonons, excitons, and their collective interactions remains limited. This study presents scalable, quadruple moiré‐pockets formed by vertically stacking chemical vapor deposition‐grown monolayer MoS ₂ –WS ₂ and MoSe ₂ –WSe ₂ lateral heterostructures with controlled θ (0⁰–60°), within a single flatland. Moiré non‐rigidity induces lattice‐relaxation via rotational reconstruction (θ<8°) and volumetric dilation (θ>8°), resulting in strain‐mediated phonon frequency‐softening and linewidth‐broadening, respectively. Strain localizes selectively in mechanically softer crystal for θ<8°, while an epitaxial‐pseudomorphic pattern dominates for θ>8°. Degree of phonon‐reconfiguration and angle‐resolved photoemission spectroscopy uncover the role of interfacial orbitals in modulating interlayer coupling. At aligned angles (θ–0° and 60°), specifically, MoS ₂ exhibits Davydov splitting and reduced valley polarization, reflecting symmetry breaking and chiral phonon effects. At θ–3°, WS ₂ /WSe ₂ shows up to 480% enhancement in second‐harmonic generation (SHG), while WS ₂ /MoSe ₂ records the lowest due to variations in interlayer‐coherence and band‐offset‐driven phase delay. Notably, at θ–60°, only WS ₂ /MoSe ₂ exhibits an anomalous 300% SHG enhancement, attributed to large phase delay and reconstruction‐induced strain. Electronic bandstructure calculations support these observations. These findings offer programmable multi‐moiré platforms for opto‐straintronics, sensing, and on‐chip quantum photonics applications.