Thermoelectric properties of Al-based icosahedral quasicrystals

Icosahedral AlPdRe quasicrystals show primarily semiconductor-like electronic properties and low thermal conductivity. We present the composition dependence of the electrical conductivity and Seebeck coefficient for icosahedral AlPdRe. The strong composition dependence is considered to be related to the pseudogap structure in the electron density of states at the Fermi energy, and to the variation in the bonding nature between Al and transition metals. The temperature dependence of the electrical properties has been analyzed using a two-band model. The results obtained suggest that the effective mass plays an important role in the improvement of thermoelectric properties. The dimensionless thermoelectric figure of merit, ZT, has a maximum value of approximately 0.1 in the temperature range from 600 to 700 K and reveals a strong composition dependence.