ON THE ELECTRONIC-PROPERTIES OF ICOSAHEDRAL QUASI-CRYSTALS

Boron, aluminium and gallium belong to the same group of the periodic system of elements and are therefore expected to generate similar bond s in specific solid state structures. Obviously such similarities lead to the icosahedra in boron-rich solids and in Al-based quasicrystals. Since the electronic band structures of the boron-rich solids are dec isively determined by electron-phonon interactions in the B-12 icosahe dra, related characteristics in the band structures of quasicrystals w ith structures based on Al-12 icosahedra are expected. Close similarit ies of optical properties of beta-rhombohedral boron interstitially do ped with transition metals and some icosahedral quasicrystals support this expectation Hence for the interpretation of the electronic proper ties of icosahedral quasicrystals a semiconductor concept similar to t hat in boron-rich solids is proposed.