Electronic transport in Cd–Yb and Y–Mg–Zn quasicrystals

Abstract

Electronic transport properties of the stable binary Cd5.7Yb quasicrystal and a quasicrystal in the Y–Mg–Zn family is presented. Electrical conductivity in these systems is an order of magnitude higher than other quasicrystals, resulting in larger thermal conductivity values due to enhanced electronic contributions (λE=L0σT). Room temperature Hall measurements provide a charge carrier density of 2.3×1021 and 3.1×1020 cm−3 in Cd5.7Yb and Y–Mg–Zn, respectively, indicating these materials have a higher carrier concentration and are better conductors than other quasicrystalline counterparts. Thermoelectric power in both Cd5.7Yb and Y–Mg–Zn have relatively small magnitudes (16 and 8 μV/K, respectively). Despite many similarities between these two systems, low temperature specific heat reveals a low Debye temperature in Cd5.7Yb(140 K) while the Debye temperature of Y–Mg–Zn and other quasicrystals is at least twice as large. Consequences of the electrical transport in these systems will be discussed.