Metallic Phase with Long‐Range Orientational Order and No Translational Symmetry

Shechtman, D.; Blech, I. A.; and, D. Gratias; Cahn, John W.

doi:10.1002/9781118788295.ch44

Cited by 224 publications

(268 citation statements)

References 73 publications

(56 reference statements)

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“…1 They possess long-range order but no translational invariance. They are a special class of complex intermetallics, in the sense that their unit cell is of infinite dimension.…”

Section: Self-organized Molecular Films With Long-range Quasiperiodicmentioning

confidence: 99%

Self-Organized Molecular Films with Long-Range Quasiperiodic Order

et al. 2014

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Self-organized molecular films with long-range quasiperiodic order have been grown by using the complex potential energy landscape of quasicrystalline surfaces as templates. The long-range order arises from a specific subset of quasilattice sites acting as preferred adsorption sites for the molecules, thus enforcing a quasiperiodic structure in the film. These adsorption sites exhibit a local 5-fold symmetry resulting from the cut by the surface plane through the cluster units identified in the bulk solid. Symmetry matching between the C60 fullerene and the substrate leads to a preferred adsorption configuration of the molecules with a pentagonal face down, a feature unique to quasicrystalline surfaces, enabling efficient chemical bonding at the molecule-substrate interface. This finding offers opportunities to investigate the physical properties of model 2D quasiperiodic systems, as the molecules can be functionalized to yield architectures with tailor-made properties. KeywordsC60, self-assembly, quasiperiodic order, scanning tunneling microscopy, density functional theory, 5-fold symmetry Disciplines Materials Chemistry | Materials Science and Engineering CommentsReprinted with permission from ACS Nano 8 (2014) Q uasicrystals (QCs) were discovered in intermetallic compounds by D. Shechtman, Nobel Prize in Chemistry 2011. 1 They possess long-range order but no translational invariance. They are a special class of complex intermetallics, in the sense that their unit cell is of infinite dimension. QCs have a fascinating beauty associated with forbidden symmetries, like five-, 10-, or 12-fold rotational symmetries not found in periodic systems. Today, the field is very active, and QCs are being discovered in a broad range of systems. Hundreds of intermetallic compounds with quasiperiodic structures have been identified in phase diagrams. 2 But QCs are no longer restricted to intermetallics. Soft QCs are an emerging field in colloidal and supramolecular chemistry. 3,4 Perovskite oxide thin films with quasiperiodic structures have recently been identified, 5 and even water thin films have been predicted to adopt quasiperiodic structures under specific conditions. 6 In this article, we show that molecular films with long-range quasiperiodic order can also be grown by using clean QC surfaces as templates, thus extending the concept of QCs to an even wider materials field.Thorough investigations of QC surfaces in an ultra-high-vacuum environment have led to the conclusion that they are bulk terminated at specific planes. 7,8 For Al-based QCs, the selected terminations are dense Al-rich planes of the bulk structure separated by the largest interplanar distances corresponding to the lowest surface energy terminations. Low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) images reveal both the long-range quasiperiodic order and local atomic configurations corresponding to cluster building blocks used to described the bulk structure that are truncated by the surface plane. 9À12 Such termin...

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“…1 They possess long-range order but no translational invariance. They are a special class of complex intermetallics, in the sense that their unit cell is of infinite dimension.…”

Section: Self-organized Molecular Films With Long-range Quasiperiodicmentioning

confidence: 99%

Self-Organized Molecular Films with Long-Range Quasiperiodic Order

et al. 2014

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“…The first report of an icosahedral quasicrystal phase exhibiting the fivefold symmetry forbidden in classical crystallography and a quasiperiodic translational order took the scientific community by surprise [1]. The reciprocal space of this crystal are densely filled with spots of various intensities, and are characterized by an icosahedral symmetry which has six fivefold symmetry axes, 10 threefold symmetry axes (through the twenty triangular faces) and 15 twofold symmetry axes.…”

Section: Introductionmentioning

confidence: 99%

Lattice Correspondence and Growth Structures of Monoclinic Mg4Zn7 Phase Growing on an Icosahedral Quasicrystal

Singh

Rosalie

2018

Crystals

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Mg 4 Zn 7 phase, with a monoclinic unit cell, a layered structure and a unique axis showing pseudo-tenfold symmetry, grows over icosahedral quasicrystalline phase in a manner similar to a decagonal quasicrystal. In this study, the relationship of this phase to icosahedral quasicrystal is brought out by a transmission electron microscopy study of Mg 4 Zn 7 phase growing on icosahedral phase in a cast Mg-Zn-Y alloy. Lattice correspondences between the two phases have been determined by electron diffraction. Planes related to icosahedral fivefold and pseudo-twofold symmetry are identified. Possible orthogonal cells bounded by twofold symmetry-related planes have been determined. Mg 4 Zn 7 phase growing on an icosahedral phase exhibits a number of planar faults parallel to the monoclinic axis, presumably to accommodate the quasiperiodicity at the interface. Two faults were identified, which were on {200} and {201} planes. Their structures have been determined by high resolution imaging in TEM. They produce two different unit cells at the interface.

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“…Com a descoberta dos quasicristais de simetria icosaedral numa liga AlMn por Shechtman et al, (1984), levaram-se uma intensa pesquisa sobre a estrutura e propriedades eletrônicas destes novos materiais [9]. Estes materiais podem ser fabricados por moagem mecânica de alta energia, por solidificação rápida ou convencional, deposição física de vapor assistida por plasma (PAPVD).…”

Section: Propriedades Eletrônicas Em Quasicristaisunclassified

PROPRIEDADES ELETRÔNICAS DA LIGA QUASICRISTALINA AlCuFe

Nascimento¹

2017

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Este trabalho tem como objetivo principal mostrar um estudo sobre o comportamento da liga quasicristalina AlCuFe com relação às suas propriedades estruturais e eletrônicas. Com relação às propriedades estruturais foi dado ênfase aos padrões de difração de raios X e por evolução microestrutural pela a microscopia eletrônica de varredura. O estudo das propriedades eletrônicas seguiu a seqüência de Fibonacci para determinar os espectros eletrônicos da liga estudada. Foi mostrado que as propriedades eletrônicas destas, representam sistemas intermediários entre ordem e desordem, em relação sequência

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Metallic Phase with Long‐Range Orientational Order and No Translational Symmetry

Cited by 224 publications

References 73 publications

Self-Organized Molecular Films with Long-Range Quasiperiodic Order

Self-Organized Molecular Films with Long-Range Quasiperiodic Order

Lattice Correspondence and Growth Structures of Monoclinic Mg4Zn7 Phase Growing on an Icosahedral Quasicrystal

PROPRIEDADES ELETRÔNICAS DA LIGA QUASICRISTALINA AlCuFe

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