Composition dependence of thermoelectric properties of AlPdRe icosahedral quasicrystals

Abstract

We present the composition dependence of the Seebeck coefficient and the electrical conductivity of AlPdRe icosahedral alloys. As the concentration of transition metal (either Pd or Re) increases, the Seebeck coefficient rapidly increases. The strong composition dependence is related to the pseudogap structure in the electron density of states at the Fermi energy, and to the variation in bonding nature between Al and transition metal. Glass-like transport behavior in thermal conduction is also observed. The dimensionless thermoelectric figure of merit has a maximum value of approximately 0.1 in the temperature range from 600 to 700 K and reveals strong composition dependence.