On Modified Mott (Т–1/4) Law in the Conductivity of Quasicrystals

Abstract

In the conductivity of quasicrystals, modified with a metal additive, numerous cases of manifestation of the Mott Т -1/4 law have been found. In the icosahedral phases of the Al-Pd-Re system, this anomaly is observed not only in the limit of the marginal metallic conductivity, as was known until now, but long before this limit is reached. It is also shown that similar anomalies are characteristic of the Al-Cu-Fe system of quasicrystalline alloys, the level of metallic conductivity of which is two to three orders of magnitude higher than that in polycrystalline Al-Pd-Re materials. It is assumed that these anomalies are the manifestation of a wide distribution of two-level excitations of "chemically" localized electrons.