Acoustic phonon dynamics in strained cubic and hexagonal GaN/Al2O3 superlattices P. D. Sesion Jr., E. L. Albuquerque, M. S. Vasconcelos, P. W. Mauriz and V. N. Freire Eur. Phys. J. B, 51 4 (2006) 583-591 Published online: 28 June 2006 DOI: 10.1140/epjb/e2006-00256-0