Electron Localization in Quasicrystals

The question of whether scattering by the almost-periodic lattice potentials of recently discovered metallic quasicrystals is able to explain the recently observed short mean free paths (about 1 Å) in these materials is discussed. It is shown that scattering by a three-dimensional, almost-periodic potential cannot account for such resistivities, but a model which includes structural defects in the three-dimensional Penrose tiling and large scattering of electrons due to $s-d$ resonant scattering can account for the experimental observations.