ELECTRON-ENERGY-LOSS SPECTROSCOPY STUDY OF A STABLE DECAGONAL QUASI-CRYSTAL AL70NI20RH10

Electron-energy-loss spectra of a stable decagonal quasicrystal Al70Ni 20Rh10 have been obtained at electron incidences parallel and perpendi cular to the decagonal axis on single-crystal areas of 180 nm diameter . Volume plasmon peaks appeared at about 17 eV for both incidences but showed full width at half-maximum values of 7.0 eV for the parallel i ncidence and 6.3 eV for the perpendicular incidence. Excitation spectr a of Al L-shell electrons for both of the incidences showed a sharp on set (Fermi edge) at an energy higher by 0.1 eV than that of aluminium. The spectra showed a small rise in intensity at the onset. This small rise corresponds to a low density of states near the Fermi level, sho wing the presence of a pseudogap. The origins of the high electrical r esistivity and of the bonding nature of the quasicrystal are discussed .