Coupled topological interface states and phonon molecules in GaAs/AlAs superlattices
Abstract
Topological interface states in one-dimensional superlattices provide spatially localized phonon modes protected by the topology of the underlying band structure. In GaAs/AlAs distributed Bragg reflectors (DBRs), such states can be engineered through band inversion between superlattices with opposite Zak phases within the Su-Schrieffer-Heeger framework. Here, we demonstrate topological phonon molecules and extended chains formed by coupled nanophononic interface states. By concatenating three superlattices with alternating topology, we realize two coupled interface states that hybridize into symmetric and antisymmetric modes, whose splitting can be tuned over tens of gigahertz by varying the reflectivity of the central DBR. Extending this concept, we engineer chains of up to N = 6 coupled interface states that form narrow topological minibands while remaining strongly localized at the interfaces. We experimentally observe these coupled states in molecular-beam-epitaxy-grown GaAs/AlAs heterostructures using time-domain pump-probe transient reflectivity measurements, and reproduce their behavior using transfer-matrix calculations and a simple analytical model for the mode splitting. These results establish topological interface states as a robust platform for engineering coupled phononic systems and tunable nanophononic architectures in the GHz regime.
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BibTeX
@article{sandeep2026coupled,
title = {{Coupled topological interface states and phonon molecules in GaAs/AlAs superlattices}},
author = {S. Sandeep and O. Colmegna and C. Xiang and E. Cardozo de Oliveira and K. Papatryfonos and M. Morassi and A. Lemaitre and N. D. Lanzillotti-Kimura},
journal = {Physical Review B},
year = {2026},
month = oct,
doi = {10.1103/m86k-4m6v},
eprint = {2605.12635},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05854657v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Coupled topological interface states and phonon molecules in GaAs/AlAs superlattices
AU - S. Sandeep
AU - O. Colmegna
AU - C. Xiang
AU - E. Cardozo de Oliveira
AU - K. Papatryfonos
AU - M. Morassi
AU - A. Lemaitre
AU - N. D. Lanzillotti-Kimura
PY - 2026
DA - 2026/10/22
JO - Physical Review B
DO - 10.1103/m86k-4m6v
UR - https://hal.science/hal-05854657v1
AB - Topological interface states in one-dimensional superlattices provide spatially localized phonon modes protected by the topology of the underlying band structure. In GaAs/AlAs distributed Bragg reflectors (DBRs), such states can be engineered through band inversion between superlattices with opposite Zak phases within the Su-Schrieffer-Heeger framework. Here, we demonstrate topological phonon molecules and extended chains formed by coupled nanophononic interface states. By concatenating three superlattices with alternating topology, we realize two coupled interface states that hybridize into symmetric and antisymmetric modes, whose splitting can be tuned over tens of gigahertz by varying the reflectivity of the central DBR. Extending this concept, we engineer chains of up to N = 6 coupled interface states that form narrow topological minibands while remaining strongly localized at the interfaces. We experimentally observe these coupled states in molecular-beam-epitaxy-grown GaAs/AlAs heterostructures using time-domain pump-probe transient reflectivity measurements, and reproduce their behavior using transfer-matrix calculations and a simple analytical model for the mode splitting. These results establish topological interface states as a robust platform for engineering coupled phononic systems and tunable nanophononic architectures in the GHz regime.
SN - 2469-9950
SN - 2469-9969
ER -