Electronic properties of quasicrystals

We present and analyze briefly partial valence and conduction band states distributions of Al 6 Mn and both crystalline and quasicrystalline AlCuFe phases of close nominal composition. Low densities of states and a pseudo-gap are found at the Fermi energy. We discuss the formation of this pseudo-gap as due to the diffraction of electronic conduction states by Bragg planes and emphasize its consequences for the densities of d states of the transition element. We discuss also briefly the transport properties of some systems like AlCuFe which show the proximity of a metal-insulator transition.