Low-temperature thermoelectric power and thermal conductivity of two icosahedral Al-Pd-Re quasicrystals

We report on a study comparing the thermoelectric power S and the thermal conductivity K of two icosahedral quasicrystals with nominal compositions Al70Pd21.4Re8.6 and Al70Pd20Re10 between 0.4 and 300 K. A remarkable sensitivity of the thermoelectric properties on the chemical composition seems to be compatible with the existence of narrow features in the electronic density of states. Our description of the thermal conductivity data reveals the dominating sources of phonon scattering at temperatures below 40 K. We also discuss the evidence for the localization of the vibrational modes at higher temperatures.