Waves in two-dimensional hexagonal crystal

Two-dimensional hexagonal crystal is investigated in this paper. The dispersion relations for both compressional and transverse waves in different directions are studied as well. The analytical results are in agreement with the experimental ones reported previously. The small amplitude but finite long wavelength nonlinear waves propagating in the hexagonal crystal are also investigated. This investigation indicates that the solitary waves propagating in the directions of either n or m are stable. (C) 2004 American Institute of Physics.