Singularity-free supertwisted atomic layers with giant circular dichroisms

Supertwisted van der Waals (vdW) multilayers—in which layers are stacked with identical interlayer twist angles—enable strong and programmable chiral light–matter interactions. However, directly synthesizing these multilayers remains challenging, as the conventional growth process typically produces supertwisted spirals containing an inevitable central singularity and substantial in-plane strain. Here, we demonstrate the growth of singularity-free supertwisted WS2 multilayers by employing a dome-shaped WS2 monolayer as a pre-deposited template. The crack line that forms on the dome acts as a dislocation line, with its two termini serving as a conjugate pair of opposite-handed screw dislocations. This configuration enables a dislocation-guided, layer-by-layer growth process that is free of topological singularities and characterized by low residual strain. The multilayers exhibit giant chiroptical responses, including a linear-optical circular dichroism (CD) of up to 10 mdeg and a second-harmonic CD of 0.81 within an ultrathin thickness of ~ 6 nm. Our work provides an effective route for growth of supertwisted multilayers and presents a programmable platform for chiral photonics. Supertwisted van der Waals multilayers show interesting chiroptical properties, but their growth process usually involves a topological singularity and in-plane strain. Here, the authors report the synthesis of singularity-free supertwisted WS2 multilayers showing linear-optical circular dichroism (CD) of up to 10 mdeg and a second-harmonic CD of up to 0.81.