Low-Temperature Conduction Mechanism Near the Metal-Insulator Transition of Al₇₀Pd_22.5Re_7.5 Quasicrystals

Abstract

We have found that near the metal-insulator transition of Al₇₀Pd_22.5Re_7.5 quasicrystal, the conductivity σ(T) obeys σ(T)=σ(0)+mT^1/3 between 1.5 K and ∼10 K on both sides of the metal-insulator transition, as found in disorder systems. This indicates that the conductivity near the metal-insulator transition of the Al–Pd–Re quasicrystals is mainly controlled by electron-electron interactions. The quantum interference theory is found to be able to interpret the conductivity of the samples in the scaling region up to 30 K. The inelastic scattering which causes the phase breaking at low temperature is chiefly due to the electron-electron scattering with the relaxation time τ_ie∼ 10^-11T^-α sec (α∼ 1.0).