Electronic Band Dispersion and Pseudogap in Quasicrystals: Angular-Resolved Photoemission Studies on Icosahedral Al70Pd21.5Mn8.5

Abstract
Angular-resolved photoelectron spectra from the fivefold surface of single-grain icosahedral Al70 Pd21.5 Mn8.5 exhibit a quasiperiodic dispersion of 300 meV at 2.3 eV binding energy. Low energy electron diffraction studies confirm quasicrystalline order at the surface. A distinct pseudogap feature is observed with a density of states near the Fermi level decreasing as a square-root power law.