We have constructed a structural solution for the Al72Ni20Co8 decagonal quasicrystal based on the quasi-unit cell picture. The solution gives a significantly improved fit to experiments compared to a previous proposal by us while retaining the feature that the fundamental, repeating cluster has broken 10-fold symmetry. We present a series of arguments, including new evidence based on high-resol...

We describe the design of a family of aperiodic PRNGs (APRNGs) introduced in [3]. We show how a one dimensional two tile cut and project quasicrystal (2TQC) used in conjunction with LCGs in an APRNG generates an infinite aperiodic pseudorandom sequence. In the suggested design, any 2TQC corresponding to unitary quadratic Pisot number combined with either one or two different LCGs can be used. 1...

We report an innovative high pressure method combining the diamond anvil cell device with the technique of picosecond ultrasonics. Such an approach allows us to measure sound velocity and attenuation of solids and liquids under pressure of tens of GPa, overcoming all the drawbacks of traditional techniques. The power of this experimental technique is demonstrated in studies of lattice dynamics ...

Based on scanning tunneling microscopy of the fivefold surface of the icosahedral Al-Cu-Fe quasicrystal and the refined structure model of the isostructural i-Al-Pd-Mn, we present evidence that the surface corresponds to bulk truncations at the positions where blocks of atomic layers are separated by larger interlayer spacings (gaps). Both step-height distribution and high resolution scanning t...

The set of points of a one-dimensional cut-and-project quasicrystal or model set, while not additive, is shown to be multiplicative for appropriate choices of acceptance windows. This leads to the definition of an associative additive graded composition law and permits the introduction of Lie algebras over such aperiodic point sets. These infinite dimensional Lie algebras are shown to be repres...

1 The dynamics of quasicrystals, the dynamics of Kähler action, symbolic dynamics, and the dynamics of self-organization 1 1.1 The non-determinism for the dynamics of quasicrystals contra non-determinism of Kähler action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 The dynamics of quasicrystals as a model for fundamental dynamics or high level symbolic...

Atomic-resolution Z-contrast images provide direct images of chemical disorder and columnar vacancies in an ideal Al-Ni-Co decagonal quasicrystal. Chemical disorder occurs in the central ring of the 2 nm clusters and involves both Al and Ni(Co) atoms. Columnar vacancies are observed in the form of closely spaced, half-occupied atomic columns in specific rings within the clusters. This structure...

Icosahedrite, ideally Al63Cu24Fe13, is a new mineral from the Khatyrka River, southeastern Chukhotka, Russia. It occurs as dark gray-black anhedral to subhedral grains up to 100 μm across, closely associated with spinel, diopside, forsterite, nepheline, sodalite, corundum, stishovite, khatyrkite, cupalite, and an unnamed phase of composition AlCuFe. Icosahedrite is opaque with a metallic luster...

We study the energetics of quasicrystals using a lattice gas simulation to sample atomic conngurations close to the quasicrystal and its approximants. The total potential energy for each connguration is calculated by summing electronic structure based pair potentials. We apply this method to study Al 73 Co 24 in a 14.4 A by 12.3 A by 8.1 A orthorhombic cell. The structures obtained are compared...