Electronic transport in quasiperiodic decagonal aluminum

We present ab initio calculations of the electronic transport properties of a hypothetical monoatomic quasiperiodic system, decagonal aluminum (d-Al). Our aim is to study the influence of quasiperiodicity on the transport properties at the example of a system which is sufficiently realistic to represent real Al-based quasicrystals, but does not involve the additional complexity of a strong s,p-d hybridization which determines the properties of many crystalline and quasicrystalline Al-transition-metal alloys. The structure of d-Al is based on the densest known quasicrystalline sphere packing, the local atomic arrangement is closely related to crystalline face-centred-cubic Al. The investigation of the transport properties of a series of six periodic approximants with increasing linear dimensions is based on a self-consistent calculation of the electronic eigenstates and the Kubo-Greenwood formula. A detailed scaling analysis demonstrates small deviations of the eigenstates from extended behavior and shows that the transport properties belong to the sub-ballistic regime, which a scaling exponent of the electronic diffusivity of ??0.6 that is somewhat larger than the quantumdiffusion limit (?=0.5), but distinctly smaller than for ballistic transport (?=1). In this sub-ballistic or overdiffusive regime the conductivity diverges in the thermodynamic limit, leading to metallic behavior.