Abstract

In twisted van der Waals materials, local atomic relaxation can alter the underlying electronic structure. Characterizing lattice reconstruction and its susceptibility to strain is essential for understanding emergent electronic states, especially in multilayers where interference between moiré lattices yields larger supermoiré patterns whose energy is highly sensitive to local stacking. Here, we image spatial modulations in the electronic character of helical trilayer graphene which indicate relaxation into a superstructure of large domains with uniform moiré periodicity. We show that the supermoiré domain size is increased by strain and can be altered in the same device while preserving the local properties within each domain. Finally, we observe higher conductance at the domain boundaries, consistent with predictions that they host counter-propagating edge modes. Our work provides real-space visualization of moiré-periodic domains, reveals two independently tunable length scales, and demonstrates strain-engineering as a route toward designing correlated topological networks at the supermoiré scale.

Abstract

In twisted van der Waals materials, local atomic relaxation can alter the underlying electronic structure. Characterizing lattice reconstruction and its susceptibility to strain is essential for understanding emergent electronic states, especially in multilayers where interference between moiré lattices yields larger supermoiré patterns whose energy is highly sensitive to local stacking. Here, we image spatial modulations in the electronic character of helical trilayer graphene which indicate relaxation into a superstructure of large domains with uniform moiré periodicity. We show that the supermoiré domain size is increased by strain and can be altered in the same device while preserving the local properties within each domain. Finally, we observe higher conductance at the domain boundaries, consistent with predictions that they host counter-propagating edge modes. Our work provides real-space visualization of moiré-periodic domains, reveals two independently tunable length scales, and demonstrates strain-engineering as a route toward designing correlated topological networks at the supermoiré scale.

Abstract

In twisted van der Waals materials, local atomic relaxation can alter the underlying electronic structure. Characterizing lattice reconstruction and its susceptibility to strain is essential for understanding emergent electronic states, especially in multilayers where interference between moiré lattices yields larger supermoiré patterns whose energy is highly sensitive to local stacking. Here, we image spatial modulations in the electronic character of helical trilayer graphene which indicate relaxation into a superstructure of large domains with uniform moiré periodicity. We show that the supermoiré domain size is increased by strain and can be altered in the same device while preserving the local properties within each domain. Finally, we observe higher conductance at the domain boundaries, consistent with predictions that they host counter-propagating edge modes. Our work provides real-space visualization of moiré-periodic domains, reveals two independently tunable length scales, and demonstrates strain-engineering as a route toward designing correlated topological networks at the supermoiré scale.

Abstract

In twisted van der Waals materials, local atomic relaxation can alter the underlying electronic structure. Characterizing lattice reconstruction and its susceptibility to strain is essential for understanding emergent electronic states, especially in multilayers where interference between moiré lattices yields larger supermoiré patterns whose energy is highly sensitive to local stacking. Here, we image spatial modulations in the electronic character of helical trilayer graphene which indicate relaxation into a superstructure of large domains with uniform moiré periodicity. We show that the supermoiré domain size is increased by strain and can be altered in the same device while preserving the local properties within each domain. Finally, we observe higher conductance at the domain boundaries, consistent with predictions that they host counter-propagating edge modes. Our work provides real-space visualization of moiré-periodic domains, reveals two independently tunable length scales, and demonstrates strain-engineering as a route toward designing correlated topological networks at the supermoiré scale.