Phys.org  July 3, 2024 Phonon engineering at the nanoscale holds immense promise for a myriad of applications. However, the design of phononic devices continues to rely on regular shapes chosen according to long-established simple rules. Researchers in Japan demonstrated an inverse design approach to create a two-dimensional phononic metasurface exhibiting a highly anisotropic phonon dispersion along the main axes of the Brillouin zone. A partial hypersonic bandgap was present along one axis, with gap closure along the orthogonal axis which was achieved through genetically optimized unit cells, with shapes exceeding conventional intuition. They experimentally validated their theoretical predictions using Brillouin […]