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Colocalized photonic and phononic topological edge states in silicon membrane structures

Nouh Krai, Gaëtan Lévêque, Bahram Djafari-Rouhani, and Yan Pennec

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Phys. Rev. Applied 26, 024071 – Published 25 August, 2026

DOI: https://doi.org/10.1103/s457-7wbk

Abstract

This paper is a contribution to the Physical Review Applied collection titled Phononics and Metamaterials.

Topological wave transport has become an important area of research in photonic and phononic systems, providing new insights into wave propagation and enabling promising technological applications. Although photons and phonons share common features in periodic media, they are fundamentally different in nature and are most often investigated separately. In this work, we present an analog of the quantum valley-Hall effect for both electromagnetic and elastic waves within a single platform. By breaking normal mirror symmetry in a graphene-like lattice, valley-polarized bandgaps are opened in both photonic and phononic band structures. Numerical simulations reveal nontrivial Berry curvature distributions and opposite valley Chern numbers, leading to the emergence of robust interface states at domain walls between topologically distinct crystals in both photonic and phononic domains. The topological nature and robustness of these edge modes are demonstrated through transmission calculations and spatial Fourier and Laplace spectral analyses, which allow a clear distinction between topological and trivial modes. This work establishes a unified platform enabling valley-Hall topology for both photonics and phononics and opens new perspectives for integrated multimodal and hybrid light-sound devices.

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This article appears in the following collection:

Phononics and Metamaterials

Physical Review Applied is pleased to present a Collection on Phononics and Metamaterials, in which diverse developments in research on sound waves are gathered to offer a comprehensive view of both the state of the art and the challenges ahead. The Collection is dedicated to the memory of Dr. Sarah Benchabane (1980–2024), honoring her outstanding contributions to phononics and wave physics. Contributions to this Collection will be published beginning in 2025 and continuing into 2026. This Collection is being curated by Guest Editors Muamer Kadic, Daniel Torrent, and Abdelkrim Khelif.

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Outline

Information

Phys. Rev. Applied 26, 024071– Published 25 August, 2026
  • Received 5 February 2026
  • Revised 21 May 2026
  • Accepted 14 July 2026
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