Anomalous electronic transport in ξ'-Al-Pd-Mn complex metallic alloy studied by spectral conductivity analysis

The ξ' giant-unit-cell phase of the Al-Pd-Mn alloy system exhibits an almost temperature-independent electrical conductivity with a value typical of metallic alloys, but an anomalously low thermal conductivity comparable to that of thermal insulators. The origin of the T-independent conductivity is analysed by determining the spectral conductivity function σ(E) from a combined analysis of the electrical conductivity σ(T) and the thermoelectric power S(T) using a phenomenological approach. It is found that the T-independence of the conductivity results from the specific form of the spectral conductivity, which shows very weak variation over an energy scale of several k(B)T around the Fermi level, but exhibits fine structure that yields observable effects in σ(T) and S(T).