Electronic transport of the icosahedral Zn–Mg–Sc quasicrystal and its 2/1 and 1/1 cubic approximants

Comparisons of the electrical resistivity and the electronic contribution to the specific heat have been made among the P-type icosahedral Zn81Mg6Sc13, and their crystalline approximants 2/1-Zn82Mg5Sc13 and 1/1-Zn85Sc15. The temperature dependence of the resistivity, ρ(T), is nearly the same for the quasicrystal and the 2/1-cubic approximant, with a negative coefficient and similar resistivity values, i.e., ρ(4.2 K)=350 and 300 μΩ cm, respectively. On the other hand, ρ(T) shows a metallic character with a positive coefficient and a rather low resistivity value of ρ(4.2 K)=150 μΩ cm for the 1/1-cubic approximant. Electronic specific heat coefficients, γ, are small as in other i-phases and approximants; 0.50, 0.42 and 0.71 mJ/(mol K2) for the quasicrystal, the 2/1- and the 1/1-approximants, respectively. The present result suggests that the electronic transport is essentially determined by the length scale of 22 Å in the P-type i-phase.