Torsional Periodic Lattice Distortions and Diffraction of Twisted 2D Materials

Abstract

Twisted 2D materials form complex moiré structures that spontaneously reduce symmetry through picoscale deformation within a mesoscale lattice. We show twisted 2D materials contain a torsional displacement field comprised of three transverse periodic lattice distortions (PLD). The torsional PLD amplitude provides a single order parameter that concisely describes the structural complexity of twisted bilayer moirés. Moreover, the structure and amplitude of a torsional periodic lattice distortion is quantifiable using rudimentary electron diffraction methods sensitive to reciprocal space. In twisted bilayer graphene, the torsional PLD begins to form at angles below 3.89° and the amplitude reaches 8 pm around the magic angle of 1.1°. At extremely low twist angles (e.g. below 0.25°) the amplitude increases and additional PLD harmonics arise to expand Bernal stacked domains separated by well defined solitonic boundaries. The torsional distortion field in twisted bilayer graphene is analytically described and has an upper bound of 22.6 pm. Similar torsional distortions are observed in twisted WS${}_2$, CrI${}_3$, and WSe${}_2$ / MoSe${}_2$.

References in corpus (4)

• Twist engineering of the two-dimensional magnetism in double bilayer chromium triiodide homostructures
• Commensurate-incommensurate phase transition in bilayer graphene
• Atomic Lattice Disorder in Charge Density Wave Phases of Exfoliated Dichalcogenides (1T-TaS2)
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Cited by in corpus (10)

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• Rotational and Dilational Reconstruction in Transition Metal Dichalcogenide Moiré Bilayers
• Observation of stacking engineered magnetic phase transitions within moiré supercells of twisted van der Waals magnets
• An atomistic insight into moiré reconstruction in Twisted Bilayer Graphene beyond the magic angle
• Endotaxial Stabilization of 2D Charge Density Waves with Long-range Order
• Considerations for extracting moiré-level strain from dark field intensities in transmission electron microscopy
• Quantifying superlubricity of bilayer graphene from the mobility of interface dislocations
• Modular hybrid machine learning and physics-based potentials for scalable modeling of van der Waals heterostructures
• Energetically Favored One-Dimensional Moiré Superstructure in the Pseudo-Square Lattice GdTe3