Thermoelectric properties of Al-Pd-Re(-Ru) icosahedral quasicrystals

Abstract

Composition dependences of thermoelectric properties of ternary AlPdRe and quaternary AlPdReRu icosahedral quasicrystals have been studied. The strong and nonmonotonous composition dependence of electrical properties is observed in both ternary and quaternary systems. The dimensionless figure of merit, ZT, changes rapidly with a slight change in Re concentration, and ranges from 0.001 to 0.1. By Ru substitution, ZT increases by a factor of 1.5 from 0.1 to 015. According to the result of two-band analysis, the composition dependence of effective mass has peaks at the peak of ZT value. We ascribe the behavior of composition dependence of effective mass to the change in the bond strength of intra- and inter-Mackay icosahedral clusters.