Fig. 3
From: Nodal rings and drumhead surface states in phononic crystals
Phononic drumhead surface states. a The projected dispersion for kya = 0 showing the surface states of the PC. The red arrows and blue arrows denote the drumhead surface states and high-frequency surface states, respectively. b A 3D view of the simulated dispersion for the drumhead surface states. The red lines show the equifrequency contour at 10.6 kHz. c Cross sections for the measured drumhead dispersion. The measured results are consistent with the variations of the simulated dispersion
