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Current Trends in the Physics of Materials: Proceedings of the Symposium

ELECTRONIC STRUCTURE OF A TWO DIMENSIONAL PENROSE LATTICE

The electronic structure of the Penrose lattice is studied using a tight-binding model. The local densities of states are calculated for 15 vertices having distinct nearest neighbors and the averaging is done exactly. The density of states shows a strong dependence on the local environment of a vertex and consists of several peaks and gaps but shows no self-similarity behavior. In conformity with a recent study we also find a-function-like localized state lying in a gap at the center of the band. {\textcopyright} 1987 The American Physical Society.

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Physical Review B

Local-environment dependence of the electronic structure of a Penrose lattice

The electronic structure of a quasiperiodic superlattice with slabs of A- and B-type layers is studied within a tight-binding model by use of the transfer matrix and a perturbative approach. It is found that the band gaps vary strongly within the two-dimensional Brillouin zone and, in the case of more than one layer in a slab, there are a few eigenvalues for each k? for which the eigenstates appear to be extended in the quasiperiodic direction. The latter is true even for the Fibonacci chain with more than one atom per cell. {\textcopyright} 1987 The American Physical Society.

Physical Review Letters

Electronic structure of a quasiperiodic superlattice

Materials Science Forum

An Atomistic Model for the Decagonal Phase of Al-Fe Alloy

Prasannan et al. (1985, Chem. Engng Sci. 40, 1251-1261) developed a mathematical model to account for the effect of inerts on gas-solid reactions. The model is experimentally verified in this paper. A reaction system involving capture of CO2 by freshly prepared lime pellets was chosen and varying amounts of inert particles were added to the reactive particles to study the effect of this addition on the progress of the reaction. These results can be of great significance in achieving better solids utilization in many industrial systems, particularly where expensive solid sorbents are used for gas removal purposes. © 1987.

Chemical Engineering Science

A experimental study of the effect of inerts on gas-solid reactions

We present a tight-binding calculation of the electronic local density of states (LDOS) and binding energy for chemisorbed oxygen on a Ni(001) surface at various coverages. The electronic structure is determined by treating explicitly the 4s and 3d electrons and their hybridization for the substrate Ni atoms and the oxygen 2p electrons. The continued-fraction technique is used to determine the LDOS. The obtained LDOS for the p(2 × 2) and c(2 × 2) structures is in good agreement with photoemission measurements. Our calculation shows that with increasing oxygen coverage, the binding energy of oxygen decreases, whereas the charge transfer on oxygen increases. These results are discussed in connection with oxidation of the surface nickel occuring at high coverages. {\textcopyright} 1986.

Surface Science

Calculation of coverage dependence of electronic density of states and binding energy for chemisorbed oxygen on Ni(001)

We study the electronic structure of a (001) face centered cubic quasi-periodic superlattice within a tight binding model using the transfer matrix method and a pertubative approach. The band gaps are found to vary strongly within the two dimensional Brillouin zone and there are a few eigenvalues for each k//1//1 for which the eigenstates appear to be extended in the quasi-periodic direction also.

Key Eng Mater

Electronic Structure of (001) Face Centered Cubic Quasi-Periodic Superlattice.

The self-similarity property of the two-dimensional Penrose lattice is utilized to characterize it in terms of the distribution of different kinds of vertices, the Voronoi cells and their nearest neighborhoods. Striking similarities are observed between the layer structures of the crystalline $\delta$-Al11Mn4, Al6Mn, Al13Fe4, Pt5P2 and Ni3Si2 with a sublattice of the Penrose lattice. The latter can be described in terms of cells which need not have fivefold rotational symmetry. Following the atomic distributions in the crystalline Al6Mn and Al13Fe4, decorations of such lattices are suggested to model the T phase of Al-Mn and other related quasicrystals. We find two types of layers with fivefold rotational symmetry in the T phase. This is in agreement with the electron diffraction from such quasicrystals. {\textcopyright} 1986 The American Physical Society.