Electronic properties of Fe clusters on a Au(111) surface

Delga, Alexandre; Lagoute, Jérôme; Repain, Vincent; Chacon, Cyril; Girard, Yann; Marathe, Madhura; Narasimhan, Shobhana; Rousset, Sylvie

doi:10.1103/physrevb.84.035416

Cited by 20 publications

(13 citation statements)

References 23 publications

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“…The evolution of the LEED pattern observed under this treatment is consistent with previous studies on the epitaxial growth of Fe on Au{111}. At low coverage iron is known to nucleate forming polygonal one atom thick islands whose spacing is determined by the underlying Au{111} herringbone reconstruction geometry [44,46,47]. These islands grow laterally with increasing coverage disrupting the underlying Au{111} surface structure, and thus decreasing the sharpness of the diffracted beams in the LEED pattern, as observed in Following Fe deposition on Au{111} we attempted the sulphurization of surface Fe by annealing this surface to 673 K in a H2S atmosphere (1x10 -6 mbar).…”

Section: Fexsy Nanoparticlessupporting

confidence: 87%

“…Midway between the hcp and fcc regions, Au atoms sit in bridge positions with respect to the second layer, running in a zig-zag manner across the surface, with a partial dislocation being situated at the turns of the zig-zag structure. It has been shown, by STM and LEED measurements, that Fe [43,44] and FexSy [45] nanoclusters preferentially nucleate at these partial dislocations, and since the nucleation sites are some distance apart, well-separated nanoclusters can be formed on this inert substrate [43,44]. This substrate seems therefore ideal to perform experiments on the chemistry of FexSy clusters, limiting the probability of sintering.…”

Section: Fexsy Nanoparticlesmentioning

confidence: 99%

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Activity of iron pyrite towards low-temperature ammonia production

2017

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In this work we report the characteristics of iron pyrite toward the production of ammonia at low temperatures under ultra-high vacuum conditions. We review (with additional unpublished details) our previous systematic study of nitrogen and hydrogen adsorption on single-crystal iron pyrite (FeS2) and summarise our earlier findings regarding the possibility of ammonia synthesis on this material. We also present new results concerning the adsorption of nitrogen and hydrogen on two related materials, namely molybdenum-treated iron pyrite surfaces and iron pyrite nanostructures deposited on a gold single-crystal. On the bare iron pyrite samples, ammonia is produced upon hydrogenation of preadsorbed N species at 230 K, demonstrating that all hydrogenation steps are possible at low pressures and temperatures. Nitrogen adsorbs molecularly on FeS2{100} at low temperatures, desorbing at 130 K, but does not adsorb dissociatively even at pressures up to 1 bar. Adsorbed nitrogen species can, however, be obtained through exposure to excited nitrogen species. Hydrogen adsorbs on FeS2{100}, but only in the presence of an incandescent Ta filament. Recombinative desorption of H2 occurs at 225 K and is accompanied by desorption of H2S at 260 K. On the molybdenum-treated iron-pyrite, no appreciable Nads species were detected under the experimental conditions studied, and the same is true for iron pyrite nanostructures on Au{111}. We also provide further details of our efficient and reproducible method for preparing wellordered stoichiometrically pure FeS2{100} suitable for surface science studies.

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Section: Fexsy Nanoparticlessupporting

confidence: 87%

Section: Fexsy Nanoparticlesmentioning

confidence: 99%

Activity of iron pyrite towards low-temperature ammonia production

2017

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“…Measurement conditions of dI=dV images: SP-STM and STS measurements (Schouteden et al, 2011). For monolayer Fe islands on Au(111), majority s-p surface states were also found in ab initio calculations (Delga et al, 2011;Donati et al, 2011;Marathe et al, 2012) and the electron confinement of the surface states was observed in differential conductance maps using STM and STS (Delga et al, 2011;Marathe et al, 2012). Bilayer Ni islands on Cu(111) are also expected to show spin-polarized s-p surface states from theory (Magaud et al, 2004) and STM and STS measurements (Pons, Mallet, and Veuillen, 2001).…”

Section: Spin-polarized Quantum Confinement On a Magnetic Nanostrumentioning

confidence: 89%

Spin-polarized quantum confinement in nanostructures: Scanning tunneling microscopy

et al. 2014

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Experimental investigations of spin-polarized electron confinement in nanostructures by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) are reviewed. To appreciate the experimental results on the electronic level, the physical basis of STM is elucidated with special emphasis on the correlation between differential conductance, as measured by STS, and the electron density of states, which is accessible in ab initio theory. Experimental procedures which allow one to extract the electron dispersion relation from energy-dependent and spatially resolved STM and STS studies of electron confinement are reviewed. The role of spin polarization in electron confinement is highlighted by both experimental and theoretical insights, which indicate variation of the spin polarization in sign and magnitude on the nanometer scale. This review provides compelling evidence for the necessity to include spatial-dependent spin-resolved electronic properties for an in-depth understanding and quantitative assessment of electron confinement in magnetic nanostructures and interaction between magnetic adatoms.

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“…22 Future work could include looking at other adsorbates such as Co, Fe, and Ti that also form nanoislands. [53][54][55] An ab initio calculation of induced resistivity of magnetic atoms on the surface of a free-electron metal by Trioni et al found that the scattering cross section can vary widely for different elements, depending on the relationship between the adatom's induced density of states and the Fermi level of the substrate. 56…”

Section: Discussionmentioning

confidence: 99%

Effects of ordered islands on surface resistivity: Ni on Au(111)

Cohen

Tobin

2017

The Journal of Chemical Physics

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The change in surface resistivity due to the formation of nickel islands on gold(111) was studied by measuring the resistance of a thin film of Au as a function of Ni coverage, θ. Previous studies showed that the Au(111) herringbone reconstruction provides a template for the periodic growth of ordered islands. Ni islands grow radially until θ ≈ 0.3 ML, after which subsequent Ni atoms contribute primarily to a second layer. Since Ni atoms on Au(111) grow in ordered nanoclusters, a nonlinear dependence of resistance on θ might be anticipated. Our results, however, show a linear dependence for Ni atoms in the first layer, as if they were independent point scatterers. Above θ ≈ 0.3 ML, there is little change in resistivity, which we attribute to Ni atoms in the second layer making no significant contribution to the resistivity. Although we did not directly image the islands, our results are consistent with the growth model and structures previously observed with scanning tunneling microscopy. Our results serve as an indirect probe of the growth kinetics of this system, as well as determining the contributions of Ni islands to the surface resistivity of the Au film.

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Electronic properties of Fe clusters on a Au(111) surface

Cited by 20 publications

References 23 publications

Activity of iron pyrite towards low-temperature ammonia production

Activity of iron pyrite towards low-temperature ammonia production

Spin-polarized quantum confinement in nanostructures: Scanning tunneling microscopy

Effects of ordered islands on surface resistivity: Ni on Au(111)

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