Electronical properties of quasicrystalline model systems: influence of phason flips

The influence of single phason Rips on the electronic properties of quasicr ystalline model systems is investigated instead of using random tiling mode ls. in a tight binding model of the Penrose lattice there are seven differe nt types of possible phason flips according to the involved vertexstars. To lerating a random number of flips of only one type simultaneously and avoid ing multiple flips the spectrum, the eigenstates and the dc-conductance of this model system as a function of the flip type are calculated. Every Rip 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 type s of flips result in smoothing out the density of states and the very stron g fluctuations of the conductance in most of the energy regions. But the st rength 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 Rips resulting in a s trong or weak effect to the conductance. So, the investigation of the condu ctance under the influence of special Rips offers the possibility to study the relevance of several local configurations to the electronic properties at a given energy. (C) 2000 Elsevier Science B.V. All rights reserved.