Surfaces of Quasicrystals and Complex Metallic Alloys

Thiel, Patricia A.; McGrath, R.

doi:10.1002/9783527680559.ch18

Cited by 3 publications

(3 citation statements)

References 179 publications

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“…Among the first such studies were those of the ten-fold surface of the decagonal phase [13,14] using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The five-fold surfaces of icosahedral quasicrystals and the ten-fold surfaces of decagonal quasicrystals in particular have received most attention [15].…”

Section: Introductionmentioning

confidence: 99%

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

Fournée

Ledieu

Gaudry

et al. 2020

Recent Advances in Thin Films

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Complex metallic alloys (CMAs) may be defined as those intermetallic compounds having large (>≈nm) unit cell dimensions. This includes quasicrystals as a special case, the unit cell being infinite. The discovery of quasicrystals motivated the study of CMAs, and the surface science community became active in the field once stable samples of sufficient size were produced. While the initial surface science activity centred on clean surface preparation, increasingly the formation of thin films, both metallic and molecular grew in importance. In this chapter we give a brief introduction to this topic, and then focus on several current areas of interest. These include the growth and characterisation of ultrathin metallic films of diverse architectures, the formation through deposition of novel molecular overlayers and thin films, complex intermetallics as surface alloys, and the potential use of intermetallic surfaces for catalytic reactions.

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Section: Introductionmentioning

confidence: 99%

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

Fournée

Ledieu

Gaudry

et al. 2020

Recent Advances in Thin Films

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“…We use a single-crystal sample to investigate the structure, composition, and stability of NaAu 2 (111) in ultrahigh vacuum. Single crystals are advantageous because their surfaces usually exhibit a terrace–step morphology, in which the atomic arrangement on the terraces and the step heights can be compared with those in the bulk structure …”

Section: Introductionmentioning

confidence: 99%

“…Single crystals are advantageous because their surfaces usually exhibit a terrace− step morphology, in which the atomic arrangement on the terraces and the step heights can be compared with those in the bulk structure. 9 No surfaces of bulk NaAu 2 have been characterized before, although a closely related system has been investigated. Barth et al studied sodium (Na) films deposited on Au(111).…”

Section: Introductionmentioning

confidence: 99%

The (111) Surface of NaAu₂: Structure, Composition, and Stability

et al. 2014

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The (111) surface of single-crystal NaAu2 is a model for catalytically active, powdered NaAu2. We prepare and characterize this surface with a broad suite of techniques. Preparation in ultrahigh vacuum consists of the traditional approach of ion bombardment (to remove impurities) and thermal annealing (to restore surface order). Both of these steps, however, cause loss of sodium (Na), and repeated treatments eventually trigger conversion of the surface and near-surface regions to crystalline gold. The bulk has a limited ability to repopulate the surface Na. Under conditions where Na depletion is minimized, electron diffraction patterns are consistent with the bulkterminated structure, and scanning tunneling microscopy reveals mesa-like features with lateral dimensions of a few tens of nanometers. The tops of the mesas do not possess fine structure characteristic of a periodic lattice, suggesting that the surface layer is disordered under the conditions of these experiments. (111) surface of single-crystal NaAu 2 is a model for catalytically active, powdered NaAu 2 . We prepare and characterize this surface with a broad suite of techniques. Preparation in ultrahigh vacuum consists of the traditional approach of ion bombardment (to remove impurities) and thermal annealing (to restore surface order). Both of these steps, however, cause loss of sodium (Na), and repeated treatments eventually trigger conversion of the surface and near-surface regions to crystalline gold. The bulk has a limited ability to repopulate the surface Na. Under conditions where Na depletion is minimized, electron diffraction patterns are consistent with the bulkterminated structure, and scanning tunneling microscopy reveals mesa-like features with lateral dimensions of a few tens of nanometers. The tops of the mesas do not possess fine structure characteristic of a periodic lattice, suggesting that the surface layer is disordered under the conditions of these experiments. Keywords

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Growth of pentacene molecules on Tsai-type quasicrystals and related crystal surfaces

Sharma

Coates

Alofi

et al. 2021

Journal of Vacuum Science &Amp; Technology A

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We present a study of the adsorption of pentacene (Pn) molecules on the high symmetry (fivefold, threefold, and twofold) surfaces of the icosahedral ( i) Ag–In–Yb quasicrystal. We also compare the results with adsorption of Pn on a surface of a periodic crystal related to this quasicrystal, the (111) surface of the Au–Al–Tb 1/1 approximant. Scanning tunneling microscopy reveals that Pn molecules on the quasicrystal surfaces are aligned along the high symmetry directions of the substrates and selectively adsorb on Yb atoms and thus exhibit quasicrystalline order. Pn molecules on the Au–Al–Tb approximant surface also preferably adopt Tb sites. The behavior of selective adsorption can be understood in terms of the geometry and electronic properties of the adsorbate and substrate. The Yb–Yb (Tb–Tb) separations are comparable to the C–C or H–H distances in a Pn molecule. Pn is an electron donor, whereas the unoccupied electronic states of the substrate are dominated by the rare earth atoms, suggesting that there is an electronic transfer between the Pn molecules and Yb (Tb) atoms.

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Surfaces of Quasicrystals and Complex Metallic Alloys

Cited by 3 publications

References 179 publications

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

The (111) Surface of NaAu₂: Structure, Composition, and Stability

Growth of pentacene molecules on Tsai-type quasicrystals and related crystal surfaces

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Surfaces of Quasicrystals and Complex Metallic Alloys

Cited by 3 publications

References 179 publications

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

Ultra-Thin Films on Complex Metallic Alloy Surfaces: A Perspective

The (111) Surface of NaAu2: Structure, Composition, and Stability

Growth of pentacene molecules on Tsai-type quasicrystals and related crystal surfaces

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Product

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The (111) Surface of NaAu₂: Structure, Composition, and Stability