Moiré-enabled chiral plasmons in twisted bilayer graphene nanoislands
Abstract
Twisting two stacked graphene layers superimposes a moiré superlattice that reshapes their electronic structure, yet how it shapes the collective optical response of finite, nanoscale bilayers remains largely unexplored. Using an atomistic tight-binding and self-consistent density-matrix approach, we compute the twist-dependent plasmonic response of twisted bilayer graphene nanoislands comprising thousands of atoms. The spectra are strongly tunable and split into two regimes at a critical angle where a single moiré wavelength spans the island; beyond it, an ordered ladder of resonances emerges whenever an integer number of moiré periods fits within the overlapping bilayer. In doped islands, the interlayer coupling also produces a moiré-enabled Born--Kuhn chiral plasmon: opposite transverse dipoles in the two layers form an electric quadrupole that hybridizes with the bright dipole, opening an anticrossing near the critical angle, with a handedness that reverses with the twist direction. Triangular islands confirm that the moiré lattice, not the flake boundary, governs both effects, establishing twist as a mechanical handle on chiral graphene plasmons.
Related
- Plasmons in twisted bilayer graphene across dispersive and flat bands
- Randomly twisted bilayer graphene: Cascade transitions
- Pressure and Proximity Tuned Twisted Bilayer Graphene
- Direct observation of flat bands in near-magic-angle twisted bilayer CVD graphene
- Tunneling characteristics of twisted double bilayer graphene heterostructures
BibTeX
@misc{husted2026moiréenabled,
title = {{Moiré-enabled chiral plasmons in twisted bilayer graphene nanoislands}},
author = {Magnus Husted and Viktor Kanstrup and Eduardo J. C. Dias and Joel D. Cox},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.39737},
eprint = {2610.39737},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.39737},
}
RIS
TY - UNPB
TI - Moiré-enabled chiral plasmons in twisted bilayer graphene nanoislands
AU - Magnus Husted
AU - Viktor Kanstrup
AU - Eduardo J. C. Dias
AU - Joel D. Cox
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.39737
UR - https://arxiv.org/abs/2610.39737
AB - Twisting two stacked graphene layers superimposes a moiré superlattice that reshapes their electronic structure, yet how it shapes the collective optical response of finite, nanoscale bilayers remains largely unexplored. Using an atomistic tight-binding and self-consistent density-matrix approach, we compute the twist-dependent plasmonic response of twisted bilayer graphene nanoislands comprising thousands of atoms. The spectra are strongly tunable and split into two regimes at a critical angle where a single moiré wavelength spans the island; beyond it, an ordered ladder of resonances emerges whenever an integer number of moiré periods fits within the overlapping bilayer. In doped islands, the interlayer coupling also produces a moiré-enabled Born--Kuhn chiral plasmon: opposite transverse dipoles in the two layers form an electric quadrupole that hybridizes with the bright dipole, opening an anticrossing near the critical angle, with a handedness that reverses with the twist direction. Triangular islands confirm that the moiré lattice, not the flake boundary, governs both effects, establishing twist as a mechanical handle on chiral graphene plasmons.
ER -