Twistronics versus straintronics in twisted bilayers of graphene and transition metal dichalcogenides

Abstract

Several numerical studies have shown that the electronic properties of twisted bilayers of graphene (TBLG) and transition metal dichalcogenides (TMDs) are tunable by strain engineering of the stacking layers. In particular, the flatness of the low-energy moiré bands of the rigid and the relaxed TBLG was found to be, substantially, sensitive to the strain. However, to the best of our knowledge, there are no full analytical calculations of the effect of strain on such bands. We derive, based on the continuum model of moiré flat bands, the low-energy Hamiltonian of twisted homobilayers of graphene and TMDs under strain at small twist angles. We obtain the analytical expressions of the strain-renormalized Dirac velocities and explain the role of strain in the emergence of the flat bands. We discuss how strain could correct the twist angles and bring them closer to the magic angle ${\theta }_m\sim 1.05^{\circ }$ of TBLG and how it may reduce the widths of the lowest-energy bands at charge neutrality of the twisted homobilayer of TMDs. The analytical results are compared with numerical and experimental findings and also with our numerical calculations based on the continuum model.

7 pages + supplemental material

References in corpus (10)

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Cited by in corpus (16)

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• Designing Moiré Patterns by Strain
• Moiré disorder effect in twisted bilayer graphene
• Highly Accurate, Reliable and Non-Contaminating Two-Dimensional Material Transfer System
• Flat-band plasmons in twisted bilayer transition metal dichalcogenides
• Interaction-Enhanced Topological Hall Effects in Strained Twisted Bilayer Graphene
• Strained Bilayer Graphene, Emergent Energy Scales, and Moire Gravity
• Intrinsic nonreciprocal bulk plasmons in noncentrosymmetric magnetic systems
• Twisted bilayer graphene reveals its flat bands under spin pumping
• Atomic relaxation and flat bands in strain-engineered transition metal dichalcogenide bilayer moiré systems
• Electronic structure and transport in materials with flat bands: 2D materials and quasicrystals
• Review of the tight-binding method applicable to the properties of moiré superlattices
• Scalable and deterministic construction of moiré superlattice in 2D materials using stressor films
• Straintronics and twistronics in bilayer graphene