ELEMENTARY EXCITATIONS IN QUASI-CRYSTALS

We present detailed ab-initio investigations of electron- and phonon s pectra in realistic models for icosahedral and decagonal quasicrystals . We show that the hierarchical dense structure of quasi-Brillouin-zon e centers and boundaries in wave-number space explains both the spiky nature of the density of states and the existence of both propagating and stationary (localized) eigenstates. The consequence of the charact er of the eigenstates for the anomalous electronic transport and magne tic properties are discussed. (C) 1997 Elsevier Science S.A.