biostudies-literatureCi PLawrence Livermore National LaboratoryBasic Energy SciencesNational Natural Science Foundation of ChinaDivision of Materials Research9027-9035https://www.ebi.ac.uk/biostudies/studies/S-EPMC9706673biostudies-literatureUnknown22(22)Twisted stacking of van der Waals materials with moiré superlattices offers a new way to tailor their physical properties via engineering of the crystal symmetry. Unlike well-studied twisted bilayers, little is known about the overall symmetry and symmetry-driven physical properties of continuously supertwisted multilayer structures. Here, using polarization-resolved second harmonic generation (SHG) microscopy, we report threefold (<i>C</i>₃) rotational symmetry breaking in supertwisted WS₂ spirals grown on non-Euclidean surfaces, contrasting the intact symmetry of individual monolayers. This symmetry breaking is attributed to a geometrical magnifying effect in which small relative strain between adjacent twisted layers (heterostrain), verified by Raman spectroscopy and multiphysics simulations, generates significant distortion in the moiré pattern. Density-functional theory calculations can explain the <i>C</i>₃ symmetry breaking and unusual SHG response by the interlayer wave function coupling. These findings thus pave the way for further developments in the so-called "3D twistronics".Nano lettersBreaking Rotational Symmetry in Supertwisted WS₂ Spirals via Moire Magnification of Intrinsic Heterostrain.PMC9706673DMR-2140304DE-FG02-09ER46664DE-AC52-07NA2734422202133Sun MLi XWu JCi PRho YJin SGrigoropoulos CPChen YZhao YfalseBreaking Rotational Symmetry in Supertwisted WS₂ Spirals via Moire Magnification of Intrinsic Heterostrain.Twisted stacking of van der Waals materials with moiré superlattices offers a new way to tailor their physical properties via engineering of the crystal symmetry. Unlike well-studied twisted bilayers, little is known about the overall symmetry and symmetry-driven physical properties of continuously supertwisted multilayer structures. Here, using polarization-resolved second harmonic generation (SHG) microscopy, we report threefold (<i>C</i>₃) rotational symmetry breaking in supertwisted WS₂ spirals grown on non-Euclidean surfaces, contrasting the intact symmetry of individual monolayers. This symmetry breaking is attributed to a geometrical magnifying effect in which small relative strain between adjacent twisted layers (heterostrain), verified by Raman spectroscopy and multiphysics simulations, generates significant distortion in the moiré pattern. Density-functional theory calculations can explain the <i>C</i>₃ symmetry breaking and unusual SHG response by the interlayer wave function coupling. These findings thus pave the way for further developments in the so-called "3D twistronics".2022-01-01T00:00:00Z2022 Nov2025-04-05T09:44:10.9Z2025-04-05T09:44:10.9ZS-EPMC97066733634699610.1021/acs.nanolett.2c03347