Chiral triclinic metamaterial crystals supporting isotropic acoustical activity and isotropic chiral phonons

Recent work predicted the existence of isotropic chiral phonon dispersion relations lowest bands connected to acoustical activity in cubic crystalline approximants three-dimensional (3D) icosahedral metamaterial quasi-crystals. While these architectures are fairly broadband and presumably robust against fabrication tolerances due orientation averaging, they extremely complex, very hard manufacture experimentally, show effects which about an order magnitude smaller compared with those ordinary highly anisotropic crystals. Here, we propose analyse a triclinic crystal exhibiting activity. These 3D truss lattices much less complex exhibit substantially larger than quasi-crystals at price being somewhat more susceptible tolerances. This susceptibility originates from fact that have tailored two transverse ‘accidental’ degeneracy momentum space.