Moiré Engineering in 2D Heterostructures with Process-Induced Strain

Abstract

We report deterministic control over moiré superlattice interference pattern in twisted bilayer graphene by implementing designable device-level heterostrain with process-induced strain engineering, a widely used technique in industrial silicon nanofabrication processes. By depositing stressed thin films onto our twisted bilayer graphene samples, heterostrain magnitude and strain directionality can be controlled by stressor film force (film stress x film thickness) and patterned stressor geometry, respectively. We examine strain and moiré interference with Raman spectroscopy through in-plane and moiré-activated phonon mode shifts. Results support systematic C${}_3$ rotational symmetry breaking and tunable periodicity in moiré superlattices under the application of uniaxial or biaxial heterostrain. Experimental results are validated by molecular statics simulations and density functional theory based first principles calculations. This provides a method to not only tune moiré interference without additional twisting, but also allows for a systematic pathway to explore different van der Waals based moiré superlattice symmetries by deterministic design.

References in corpus (5)

• Uniaxial Strain in Graphene by Raman Spectroscopy: G peak splitting, Gruneisen Parameters and Sample Orientation
• Observation of Moiré Excitons in WSe2/WS2 Heterostructure Superlattices
• Optical Separation of Mechanical Strain from Charge Doping in Graphene
• An atomistic insight into moiré reconstruction in Twisted Bilayer Graphene beyond the magic angle
• Ultrasonic Delamination Based Adhesion Testing for High-Throughput Assembly of van der Waals Heterostructures

Cited by in corpus (9)

• Strain induced quasi-unidimensional channels in twisted moiré lattices
• Designing Moiré Patterns by Strain
• An atomistic insight into moiré reconstruction in Twisted Bilayer Graphene beyond the magic angle
• Interlayer electric multipoles induced by in-plane field from quantum geometric origins
• Designing Moire Patterns by Shearing
• Geometrical properties of strained and twisted moiré heterostructures
• Twistraintronics in Square Moire Superlattices of Stacked Graphene Layers
• Straintronics and twistronics in bilayer graphene
• Epitaxial two-dimensional membranes under intrinsic and extrinsic strains