Insulator-like electrical transport in Al_65−xSi_xCu₂₀Ru₁₅ (x=0.0, 0.5, 1.0, 1.5, 2.0) icosahedral quasicrystals

Abstract

Low-temperature resistivity and magneto-resistance have been measured from 2.8 to 300 K for stable icosahedral quasicrystals Al_65–x Si _x Cu₂₀Ru₁₅ (x = 0.0, 0.5, 1.0, 1.5, 2.0). The low-temperature σ–T behavior, in the temperature range 2.8–15 K, for the Si-substituted samples are drastically different from undoped samples. The in-field σ–T for the Si-undoped sample has been found to follow ln σ vs. T ^−1/4 below 5 K, indicating that this sample lies in the insulating side of the metal–insulator (MI) transition. The substitution of silicon at the aluminum site drives the Al–Cu–Ru quasicrystals to the metallic side of MI transition.