ELECTRONIC-PROPERTIES OF QUASI-CRYSTALS

We present and analyze briefly partial valence and conduction band sta tes distributions of Al6Mn and both crystalline and quasicrystalline A lCuFe phases of dose nominal composition. Low densities of states and a pseudogap are found at the Fermi energy. We discuss the formation of this pseudo-gap as due to the diffraction of electronic conduction st ates by Bragg planes and emphasize its consequences for the densities of d states of the transition element. We discuss also briefly the tra nsport properties of some systems like AlCuFe which show the proximity of a metal-insulator transition.