Structure of the tenfold<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>d</mml:mi></mml:math>-Al-Ni-Co quasicrystal surface

Ferralis, Nicola; Pussi, Katariina; Cox, Erik J.; Gierer, M.; Ledieu, J.; Fisher, I. R.; Jenks, Cynthia J.; Lindroos, M.; McGrath, R.; Diehl, Renee D.

doi:10.1103/physrevb.69.153404

Cited by 54 publications

(88 citation statements)

References 34 publications

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“…A hard wall at 10 nm above the surface along z is used to confine the coexisting vapor phase. The simulation results for Xe over QC, presented below, are consistent with both our results from experiments [31] and virial calculations [32]. Hence, the calculations may also be accurate for other systems.…”

Section: Unit Cellsupporting

confidence: 87%

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Noble gas films on a decagonal AlNiCo quasicrystal

Diehl¹,

Ferralis²,

Cole³

et al. 2006

J. Phys.: Condens. Matter

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Abstract. Thermodynamic properties of Ne, Ar, Kr, and Xe adsorbed on an Al-NiCo quasicrystalline surface (QC) are studied with Grand Canonical Monte Carlo by employing Lennard-Jones interactions with parameter values derived from experiments and traditional combining rules. In all the gas/QC systems, a layer-by-layer film growth is observed at low temperature. The monolayers have regular epitaxial fivefold arrangements which evolve toward sixfold close-packed structures as the pressure is increased. The final states can contain either considerable or negligible amounts of defects. In the latter case, there occurs a structural transition from five to sixfold symmetry which can be described by introducing an order parameter, whose evolution characterizes the transition to be continuous or discontinuous as in the case of Xe/QC (first-order transition with associated latent heat). By simulating fictitious noble gases, we find that the existence of the transition is correlated with the size mismatch between adsorbate and substrate's characteristic lengths. A simple rule is proposed to predict the phenomenon.

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Section: Unit Cellsupporting

confidence: 87%

“…QC, determined from the momentum transfer analysis of LEED patterns [31] (our QC surface has λ r =0.381 nm [31]). With such ad hoc definition, δ m measures the mismatch between an adsorbed {111} fcc plane of adatoms and the QC surface.…”

Section: Discussionmentioning

confidence: 99%

Noble gas films on a decagonal AlNiCo quasicrystal

Diehl¹,

Ferralis²,

Cole³

et al. 2006

J. Phys.: Condens. Matter

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show abstract

“…Although advances in computers have steadily increased the complexity of surface structures solved using LEED, quasicrystals pose an exceptional challenge because their unit cells are infinite. This requires the use of approximations, such as replacing individual atoms with average distributions [11][12][13][14] or using structure models for true periodic structures (quasicrystal approximants) that have local features similar to those in the quasicrystal [15][16][17]. The former approach suffers from lack of specific information about the positions of the atoms in the crystal, while the latter suffers from a limitation on the feasible size of the approximant model, which is about 65 atoms per layer in the largest approximant used so far [17].…”

Section: Introductionmentioning

confidence: 99%

X-ray standing wave study of Si clusters on a decagonal Al-Co-Ni quasicrystal surface

et al. 2015

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Quantitative adsorption structure determinations on quasicrystals are scarce because most techniques for measuring surface structures are not well suited to the complex and infinite unit cells of quasicrystals. The normal incidence standing x-ray wave field technique presents a solution to these problems because it can be made inherently surface sensitive and does not involve extensive computational effort. We describe a method for applying this technique to adsorbates on quasicrystals, with specific application to a submonolayer of Si atoms on a decagonal Al-Co-Ni surface. We demonstrate the sensitivity of the technique to both adsorption site and geometry, leading to the conclusion that the Si atoms, which form 6-atom pentagonal clusters, have an average height of 1.77 ± 0.05 Å above pentagonal hollow sites, with a significant height variation among the Si atoms in the cluster. In particular, the central Si atom sits more deeply than the five surrounding Si atoms, which are, on average, 2.7 Å away from the central Si atom. Although this study was performed on a decagonal quasicrystal that is periodic perpendicular to the surface, we describe how the technique can be applied to cases where that is not true.

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“…The 10-fold surface of the Al-Ni-Co decagonal quasicrystal-the surface that is quasicrystalline in both dimensions-has been studied by low-energy electron diffraction ͑LEED͒, ion scattering spectroscopy, and scanning tunneling microscopy 6-10 ͑STM͒, but there are still important issues, such as atomic structure and composition, that remain controversial. 8,9 Some authors have attributed sites of high tunneling probability in the STM images to transition metal atoms, 8 while others have identified these sites as Al atoms. 7,9 A further point of discussion is whether the surface termination is enriched in Al relative to the bulk composition.…”

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confidence: 99%

“…5 We examined three models. 8,[20][21][22] First we consider the model of Deloudi et al 21 for the Co-rich phase of decagonal Al-Co-Ni. This model is based on a columnar cluster with 20 Å diameter extracted from the W approximant, Al 72.5 Co 20 Ni 7.5 .…”

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confidence: 99%