Potential slow surface waves in pentamode materials

Slow waves are of significant interest for enhancing imaging resolution, improving detection sensitivity, etc. In this study, we investigate the possibility of slow waves emerging on the surface of solid pentamode materials. Specifically, when a uniform vertical excitation is applied to the bottom surface of a pentamode slab, periodic waveform oscillations appear on the top surface. Further analysis indicates that this surface wave owns a dispersion relation similar to the Rayleigh wave, which has a wavelength about 1/100 of that in common solid material, and can be readily excited via longitudinal and transverse coupling.