Propagating and confined vibrational excitations in quasicrystals

摘要: The authors present detailed investigations of vibrational modes in a hierarchy rational (or commensurate) approximants to icosahedral quasicrystals based on exact diagonalization the dynamical matrix and recursion calculations spectrum. results demonstrate existence well defined longitudinal transverse acoustic with isotropic dispersion relations vicinity quasiperiodically distributed special points wavenumber space, ' Gamma points' reciprocal quasilattice. Stationary eigenmodes are found around other high-symmetry space corresponding quasi-Brillouin zone boundaries. show that strictly localized ('confined') exist their origin is local topological frustration, i.e. deviation from ideal packing.