A soft-clamped topological waveguide for phonons
成果类型：
Article
署名作者：
Xi, Xiang; Chernobrovkin, Ilia; Kosata, Jan; Kristensen, Mads B.; Langman, Eric; Sorensen, Anders S.; Zilberberg, Oded; Schliesser, Albert
署名单位：
University of Copenhagen; Niels Bohr Institute; University of Copenhagen; Niels Bohr Institute; Swiss Federal Institutes of Technology Domain; ETH Zurich; University of Konstanz
刊物名称：
Nature
ISSN/ISSBN：
0028-2332
DOI：
10.1038/s41586-025-09092-x
发表日期：
2025-06-26
关键词：
摘要：
Topological insulators were originally discovered for electron waves in condensed-matter systems. Recently, this concept has been transferred to bosonic systems such as photons1 and phonons2, which propagate in materials patterned with artificial lattices that emulate spin-Hall physics. This work has been motivated, in part, by the prospect of topologically protected transport along edge channels in on-chip circuits2,3. In principle, topology protects propagation against backscattering, but not against loss, which has remained limited to the dB cm-1 level for phononic waveguides, whether topological4, 5, 6-7 or not8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18-19. Here we combine advanced dissipation engineering20-in particular, the recently introduced method of soft clamping21-with the concept of valley-Hall topological insulators for phonons22, 23, 24, 25-26. This enables on-chip phononic waveguides with propagation losses due to dissipation of 3 dB km-1 at room temperature, orders of magnitude below any previous chip-scale devices. The low losses also allow us to accurately quantify backscattering protection in topological phononic waveguides, using high-resolution ultrasound spectroscopy. We infer that phonons follow a sharp, 120 degrees bend with a 99.99% probability instead of being scattered back, and less than one phonon in a million is lost. Our work will inspire new research directions on ultralow-loss phononic waveguides and will provide a clean bosonic system for investigating topological protection and non-Hermitian topological physics.