Structure and phases of the Au(111) surface: X-ray-scattering measurements

Sandy, Alec; Mochrie, S. G. J.; Zehner, D. M.; Huang, Keqing; Gibbs, Doon

doi:10.1103/physrevb.43.4667

Cited by 252 publications

(114 citation statements)

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“…The top reconstructed layer is slightly relaxed outwards by 3.8% compared to the bulk interlayer distance, which correspond well with the value obtained previously with the same technique in vacuum (3.3%). 60 The fits also indicate 6% higher atomic density in the topmost layer compared to the bulk as expected for the compressed HB reconstruction.…”

Section: Resultssupporting

confidence: 57%

Electrochemical Formation of Germanene: pH 4.5

Ledina

Bui

Liang

et al. 2017

J. Electrochem. Soc.

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Germanene is a single layer allotrope of Ge, with a honeycomb structure similar to graphene. This report concerns the electrochemical formation of germanene in a pH 4.5 solution. The studies were performed using in situ Electrochemical Scanning Tunneling Microscopy (EC-STM), voltammetry, coulometry, surface X-ray diffraction (SXRD) and Raman spectroscopy to study germanene electrodeposition on Au(111) terraces. The deposition of Ge is kinetically slow and stops after 2–3 monolayers. EC-STM revealed a honeycomb (HC) structure with a rhombic unit cell, 0.44 ± 0.02 nm on a side, very close to that predicted for germanene in the literature. Ideally the HC structure is a continuous sheet, with six Ge atoms around each hole. However, only small domains, surrounded by defects, of this structure were observed in this study. The small coherence length and multiple rotations domains made direct observation with surface X-ray diffraction difficult. Raman spectroscopy was used to investigate the multi-layer Ge deposits. A peak near 290 cm−1, predicted to correspond to germanene, was observed on one particular area of the sample, while the rest resembled amorphous germanium. Electrochemical studies of germanene showed limited stability when exposed to oxygen.

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Section: Resultssupporting

confidence: 57%

Electrochemical Formation of Germanene: pH 4.5

Ledina

Bui

Liang

et al. 2017

J. Electrochem. Soc.

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“…This is too small to observe the Au͑111͒ surface reconstruction ͓23ϫ)͔ ͑see Ref. 44, and references therein͒ but we are confident that this will not change our main conclusion. Recent calculations in our group on the adsorption of O 2 on Au͑111͒ showed that the results are converged with only two layers.…”

Section: Computational Detailsmentioning

confidence: 72%

Binding of propene on small gold clusters and on Au(111): Simple rules for binding sites and relative binding energies

Chrétien

Gordon

Metiu

2004

The Journal of Chemical Physics

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We use density functional theory(DFT) to investigate the bonding of propene to small gas-phase gold clusters and to a Au(111) surface. The desorption energy trends and the geometry of the binding sites are consistent with the following set of rules.(1) The bond of propene to gold is formed by donation of electron density from the highest occupied molecular orbital (HOMO) of propene to one of the low-lying empty orbitals [denoted by LUMO1, LUMO2, … (LUMO-lowest unoccupied molecular orbital)] of the gold cluster. (2) Propene binds to a site on the Au cluster where one of the low-lying LUMOs protrudes in the vacuum. Different isomers (same cluster, but different binding sites for propene) correspond to sites where different low-lying LUMOs protrude in space. (3) The desorption energy of the lowest energy isomer correlates with the energy of the lowest empty orbital of the cluster; the lower the energy of that LUMO, the higher the desorption energy. (4) If the lowest-lying LUMO protrudes into space at two nonequivalent sites at the edge of a cluster, propene binds more strongly to the site with the lowest coordination. These rules are consistent with the calculated bond energies and geometries for [Aun(C3H6)]q, for n=1−5 and n=8 and q=−1, 0, +1. Based on them we have made a number of predictions that have been confirmed by DFT calculations. The bond of propene to gold is strengthened as the net charge of the cluster varies from −1, to zero, to +1. Compared to a gas-phase cluster, a cluster on a support binds propene more strongly if the support takes electron density from the cluster (e.g., a Au cluster on a goldsurface) and more weakly if the support donates electron density to the cluster (e.g., a Au cluster on an oxygen vacancy on an oxide surface). KeywordsGold, Binding sites, Density functional theory, Desorption, Oxide surfaces Disciplines Chemistry CommentsThe following article appeared in Journal of Chemical Physics 121 (2004) We use density functional theory ͑DFT͒ to investigate the bonding of propene to small gas-phase gold clusters and to a Au͑111͒ surface. The desorption energy trends and the geometry of the binding sites are consistent with the following set of rules. ͑1͒ The bond of propene to gold is formed by donation of electron density from the highest occupied molecular orbital ͑HOMO͒ of propene to one of the low-lying empty orbitals ͓denoted by LUMO1, LUMO2, ... ͑LUMO-lowest unoccupied molecular orbital͔͒ of the gold cluster. ͑2͒ Propene binds to a site on the Au cluster where one of the low-lying LUMOs protrudes in the vacuum. Different isomers ͑same cluster, but different binding sites for propene͒ correspond to sites where different low-lying LUMOs protrude in space. ͑3͒ The desorption energy of the lowest energy isomer correlates with the energy of the lowest empty orbital of the cluster; the lower the energy of that LUMO, the higher the desorption energy. ͑4͒ If the lowest-lying LUMO protrudes into space at two nonequivalent sites at the edge of a cluster, propene binds more strong...

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“…The implications of this superstructure are a multitude of extra spots amongst the satellite spots 31,32 . As seen in the insets of Fig.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Epitaxial Single-Layer MoS₂ on Au(111)

et al. 2015

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We present a method for synthesizing large area epitaxial single-layer MoS2 on the Au(111) surface in ultrahigh vacuum. Using scanning tunneling microscopy and low energy electron diffraction, the evolution of the growth is followed from nanoscale single-layer MoS2 islands to a continuous MoS2 layer. An exceptionally good control over the MoS2 coverage is maintained using an approach based on cycles of Mo evaporation and sulfurization to first nucleate the MoS2 nano-islands and then gradually increase their size. During this growth process the native herringbone reconstruction of Au (111) is lifted as shown by low energy electron diffraction measurements. Within these MoS2 islands, we identify domains rotated by 60• that lead to atomically sharp line defects at domain boundaries. As the MoS2 coverage approaches the limit of a complete single-layer, the formation of bilayer MoS2 islands is initiated. Angle-resolved photoemission spectroscopy measurements of both single and bilayer MoS2 samples show a dramatic change in their band structure around the center of the Brillouin zone. Brief exposure to air after removing the MoS2 layer from vacuum is not found to affect its quality.

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Structure and phases of the Au(111) surface: X-ray-scattering measurements

Cited by 252 publications

References 50 publications

Electrochemical Formation of Germanene: pH 4.5

Electrochemical Formation of Germanene: pH 4.5

Binding of propene on small gold clusters and on Au(111): Simple rules for binding sites and relative binding energies

Synthesis of Epitaxial Single-Layer MoS₂ on Au(111)

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Structure and phases of the Au(111) surface: X-ray-scattering measurements

Cited by 252 publications

References 50 publications

Electrochemical Formation of Germanene: pH 4.5

Electrochemical Formation of Germanene: pH 4.5

Binding of propene on small gold clusters and on Au(111): Simple rules for binding sites and relative binding energies

Synthesis of Epitaxial Single-Layer MoS2 on Au(111)

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Product

Resources

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Synthesis of Epitaxial Single-Layer MoS₂ on Au(111)