Electronic structures in quasicrystals.

Abstract The electronic structures are calculated for crystalline approximants of icosahedral quasicrystals, i-AlMn and i-AlCuLi. The density of states shows, commonly, a large depression, called a pseudogap, at the Fermi energy. The origin of the pseudogap is attributed to the electron-lattice interaction known as the Hume-Rothery mechanism. The density of states has also a structure of dense and fine spiky peaks. These may cause a large effective mass and may be one of the causes of abnormal transport phenomena and optical conductivity in quasicrystals.