Magic-free coexisting photonic and phononic moiré flat bands
Abstract
Moiré flat bands enhance localization and interactions through suppressed group velocity, but existing approaches largely target a single physical field because distinct excitations generally require different, finely tuned magic configurations. Here we introduce a flat-band mechanism based on strong diffractive hybridization among moiré-folded bands. Period-mismatched modulations open distinct coupling channels whose hybridization renormalizes the band dispersion. An effective Hamiltonian shows that increasing the diffractive coupling progressively suppresses the group velocity, driving the system toward a flat-band regime without field-specific magic configurations. This coupling-induced mechanism enables band flattening across distinct physical excitations. We demonstrate this mechanism in a single-layer moiré optomechanical crystal, where photonic and phononic flat bands are simultaneously realized, and their localized modes and optomechanical interaction are experimentally observed. Beyond photonic and phononic systems, this mechanism may extend to other wave and quasiparticle platforms, providing a general route to co-localizing and coupling distinct physical fields in moiré systems.
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BibTeX
@misc{chen2026magicfree,
title = {{Magic-free coexisting photonic and phononic moiré flat bands}},
author = {Ziming Chen and Kaiyu Cui and Ning Wu and Shuyuan Li and Chenxuan Wang and Xue Feng and Fang Liu and Wei Zhang and Hao Sun and Yongzhuo Li and Yidong Huang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.08455},
eprint = {2609.08455},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.08455},
}
RIS
TY - UNPB
TI - Magic-free coexisting photonic and phononic moiré flat bands
AU - Ziming Chen
AU - Kaiyu Cui
AU - Ning Wu
AU - Shuyuan Li
AU - Chenxuan Wang
AU - Xue Feng
AU - Fang Liu
AU - Wei Zhang
AU - Hao Sun
AU - Yongzhuo Li
AU - Yidong Huang
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.08455
UR - https://arxiv.org/abs/2609.08455
AB - Moiré flat bands enhance localization and interactions through suppressed group velocity, but existing approaches largely target a single physical field because distinct excitations generally require different, finely tuned magic configurations. Here we introduce a flat-band mechanism based on strong diffractive hybridization among moiré-folded bands. Period-mismatched modulations open distinct coupling channels whose hybridization renormalizes the band dispersion. An effective Hamiltonian shows that increasing the diffractive coupling progressively suppresses the group velocity, driving the system toward a flat-band regime without field-specific magic configurations. This coupling-induced mechanism enables band flattening across distinct physical excitations. We demonstrate this mechanism in a single-layer moiré optomechanical crystal, where photonic and phononic flat bands are simultaneously realized, and their localized modes and optomechanical interaction are experimentally observed. Beyond photonic and phononic systems, this mechanism may extend to other wave and quasiparticle platforms, providing a general route to co-localizing and coupling distinct physical fields in moiré systems.
ER -