Influence of phason flips on electronical properties of quasicrystalline model systems

Abstract

The influence of single phason flips on the electronic properties of quasicrystalline model systems is investigated instead of using random tiling models. In a tight binding model of the Penrose lattice there are seven different types of possible phason flips according to the involved vertex stars. Tolerating a random number of flips of only one type simultaneously and avoiding multiple flips the spectrum, the eigenstates and the dc conductance of this model system as a function of the flip type are calculated. Every flip in the lattice leads to a defect state localized at the flipped atom sites with an eigenenergy outside the spectrum of the unflipped lattice. All types of flips result in smoothing out the density of states and very strong fluctuations of the conductance in most of the energy regions. But the strength of this effect at a given energy depends strongly on the type of the flips in the lattice. A certain quasicrystalline pattern showing resonance at this energy can be more or less influenced by the flips, resulting in a strong or weak effect to the conductance. So the investigation of the conductance under the influence of special flips offers the possibility to study the relevance of several local configurations to the electronic properties at a given energy.