COMPARTMENTALIZATION AND OPTICAL CONDUCTIVITY IN AL-CU-FE

The frequency and temperature dependence of the optical conductivity of Al-Cu-Fe in quasicrystalline and rhombohedral phases is linear from approximately 0.03eV up to energies E(c) = HBAR-omega(max) approximately 1 eV. A microscopic compartmentalization model explains how this happens in Al-Cu-Fe and predicts E(c) in other quasicrystals. The model explains the various signs of the Hall voltages in the crystalline, quasicrystalline and amorphous phases of Al-Cu-Fe. It also explains both the successes and the failures of the pair hopping model for the linear conductivity of weakly compensated semiconductor impurity bands.