A5028398762- Surface and Thin Film Phenomena
- Advanced Chemical Physics Studies
- Magnetic properties of thin films
- Graphene research and applications
- Electron and X-Ray Spectroscopy Techniques
- ZnO doping and properties
- Copper Interconnects and Reliability
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- nanoparticles nucleation surface interactions
- Molecular Junctions and Nanostructures
- Heusler alloys: electronic and magnetic properties
- Semiconductor materials and interfaces
- Advanced Materials Characterization Techniques
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Zeolite Catalysis and Synthesis
- Boron and Carbon Nanomaterials Research
- Metal and Thin Film Mechanics
- Catalytic Processes in Materials Science
- Synthesis and Properties of Aromatic Compounds
- Photonic and Optical Devices
- Surface Chemistry and Catalysis
- Fullerene Chemistry and Applications
Université de Strasbourg
2018-2024
Institut de Sciences des Matériaux de Mulhouse
2009-2024
Université de Haute-Alsace
2008-2023
Centre National de la Recherche Scientifique
2013-2023
Centre de Gestion Scientifique
2003
Laboratoire de Photochimie et d'Ingénierie Macromoléculaire
1992-2002
Laboratoire de Spectrométrie Ionique et Moléculaire
1997
Western University
1994-1996
Germanene, a 2D honeycomb structure similar to silicene, has been fabricated on Al(111). The germanene layer covers uniformly the substrate with large coherence over Al(111) surface atomic plane. It is characterized by (3 × 3) superstructure respect lattice, shown low energy electron diffraction and scanning tunnelling microscopy. First-principles calculations indicate that Ge atoms accommodate in very regular configuration buckled conformation.
The electronic structure of germanene is investigated by high resolution photoemission and density functional theory calculations. core level Al 2p Ge 3d lines are measured on grown Al(111) using synchrotron radiation. line shifted toward the low binding energies with respect to bulk Ge, shows three components, reflecting sites multiplicity atomic structure. calculations reveal a sizable charge localization at germanene/Al(111) interface, transfer from surface atoms germanene, existence...
The treatment of Ge(100) in an aqueous ammonium sulfide solution is investigated by means x-ray photoelectron spectroscopy, Auger electron low-energy diffraction, scanning microscopy, and atomic force microscopy. This shown to produce S-passivated Ge(100)-(1×1) surface, where the S atoms appear be bridge bonded Ge atoms. Desorption observed occur between 460 750 K results a surface with morphology similar that initial sample.
Two-dimensional (2D) honeycomb lattices beyond graphene, such as germanene, appear very promising due to their outstanding electronic properties, the quantum spin Hall effects. While there have been many claims of germanene monolayers up now, no experimental evidence a structure has provided now for these grown monolayers. Using scanning tunneling microscopy (STM), surface X-ray diffraction (SXRD), and density functional theory, we elucidated Ge-induced (109×109)R±24.5° reconstruction on...
This paper proposes a new technique for the epitaxial growth of Fe on GaAs(100) which eliminates problems substrate interdiffusion through overlayer. S-passivation surface prior to overgrowth is shown be an effective way inhibiting As and Ga into The resulting layer found grow in bcc (100) orientation ferromagnetic coverages >4 monolayers.
The (3 × 3) silicene on the (4 4) Ag(1 1 1) surface is investigated by means of density functional theory calculations. We focus nature interactions between and Ag surface, in particular terms spatial charge localisation. No true covalent bonds are formed but there an overlap densities bottom Si atoms nearest atoms. Charge difference calculations show that a clear reorganisation takes place when bringing together substrate. According to Bader calculations, top slightly positively charged,...
A new germanene crystallographic structure is investigated by scanning tunnelling microscopy and density functional theory calculations. We found that can crystallize in two stable but different structures when grown on Al(111) at the same temperature. These are evidenced images a honeycomb contrast hexagonal contrast. contrasts relevant of Ge network with one (hexagonal) or (honeycomb) atoms per unit cell shifted upward respect to other atoms. appear alternatively be turned off tip-induced process.
We have used angle-resolved photoemission, low-energy electron diffraction, and work-function measurements to probe the crystallographic electronic structure of Cr/Au(100) interface formed at temperatures in 300--500-K range. The first Cr monolayers (ML) diffuse inward occupy Au lattice sites, forming a random substitutional ${\mathrm{Au}}_{100\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Cr}}_{\mathrm{x}}$ fcc alloy with concentration increasing gradually up \ensuremath{\sim}50% coverage....
Thanks to differential functional theory calculations, we show that a benzene molecule can be chemisorbed in the butterfly configuration on (3 × 3) silicene/(4 4) Ag(111) surface by means of two Si–C covalent bonds.
The growth mode of Cr on Ag(100) in the monolayer range has been studied by structure-sensitive methods. data demonstrate that a flat single is formed when substrate temperature ${\mathit{T}}_{\mathit{S}}$ kept at 430--450 K during deposition one layer equivalent, contrast with lower (higher) ${\mathit{T}}_{\mathit{s}}$ where multilayer formation (agglomeration) takes place. stable up to 460 and electron diffraction low energies (\ensuremath{\le}30 eV) reveals weak but distinct...
In the present study, we have combined several atomic-scale computational techniques [static lattice optimization, density functional theory (DFT), canonical Monte Carlo (MC), and Gibbs ensemble MC (GEMC)] with experiment in order to describe adsorption of water potassium-exchanged X-type faujasite. Indeed, by applying DFT calculations, evidenced a strongly heterogeneous adsorbent surface classified preferential sites at zero loading for molecules. The sodalite cage was identified as...
We have carefully investigated the possibility of preparing a well-ordered $p(1\ifmmode\times\else\texttimes\fi{}1)$ two-dimensional Mn monolayer on Ag(001) by means photoelectron diffraction. It is found that flat (ML) with good degree perfection actually achieved deposition at low rates (typically 0.1--0.2 ML/min) substrate held 80 K. Substrate temperatures higher than $\ensuremath{\sim}130\mathrm{K}$ invariably result in exchange adatoms Ag and formation surface alloy. Valence-band...
Auger electron spectroscopy, low-energy diffraction, thermal desorption and scanning microscopy have been utilized to investigate the stability of S-passivated InP(100). InP(100) is shown be thermally stable up ∼730 K, where S removal sample evaporation begins. This results in formation a roughened, but clean, surface, showing characteristic (4×2) reconstruction.
Angle-resolved photoemission is used to study the electronic structure of Cr layers obtained by condensing one layer equivalent (LE), or less, on Ag(100) at low (\ensuremath{\sim}0.5 LE/min) deposition rates. The data confirm our earlier finding that, upon a mildly (\ensuremath{\sim}440 K) heated substrate, layer-by-layer growth takes place up 1 LE, i.e., an ordered flat monolayer with good degree perfection formed. substrate temperature during critical since lower (\ensuremath{\sim}300...
Silicene and germanene freestanding layers are usually described as a honeycomb lattice formed by two hexagonal sub-lattices presenting height difference, namely the layer buckling. In this work, first-principles calculations show that silicene can be rippled at 0 K with various wavelengths, without any compressive strain of layer. For germanene, difference between Ge atoms from same sub-lattice high 4.7 for an undulation length 81 . The deformations related to slight (lower than 1.7°) bond...
We have determined the optimum geometry of S-passivated InP(100)-(1\ifmmode\times\else\texttimes\fi{}1) surface by dynamical low-energy electron-diffraction analysis. S atoms bond to In occupying bridge site that continues zinc-blende stacking sequence substrate. Other potential high-symmetry adsorption sites (atop, antibridge, and hollow) can be clearly ruled out. The overlayer-substrate interlayer spacing is found 1.445\ifmmode\pm\else\textpm\fi{}0.033 \AA{}, topmost substrate...
Ultrathin Mn films deposited at room temperature (RT) in ultrahigh vacuum on Ag(100) were investigated using ion scattering spectroscopy (ISS), angle-resolved ultraviolet photoemission (ARUPS) and low-energy electron diffraction (LEED). Up to \ensuremath{\sim}1 ML, ISS ARUPS definitely indicate that the Mn/Ag(100) interface is unstable RT. We find with time an Ag enrichment of film surface takes place eventually formation a two-dimensional (2D) p(1\ifmmode\times\else\texttimes\fi{}1) layer...
We present a dynamical low-energy electron diffraction analysis of the atomic and magnetic structure obtained by deposition 0.9 Mn monolayers on Ag(001) held at 100 K. find that film grows in an essentially flat ideal monoatomic layer with located fourfold hollow sites substrate undergoes no sizeable reconstruction its topmost layers. The Mn-Ag interlayer distance ${d}_{12}=2.00\ifmmode\pm\else\textpm\fi{}0.03\AA{}$ is found to be much larger than \ensuremath{\sim}1.85 \AA{} expected from...
Core-level photoemission experiments on the Cr/Au(100) interface formed at \ensuremath{\approx}120\ifmmode^\circ\else\textdegree\fi{}C reveal dramatic multiplet structure indicating presence of large local magnetic moments ($\ensuremath{\approx}4.9{\ensuremath{\mu}}_{B}$) Cr species. Surprisingly, these features persist up to approximately three monolayers along with important chemical shifts and a Cr-induced valence-band peak \ensuremath{\approx}1 eV binding energy. The latter is...
The interactions between the Ge atoms of a germanene layer and an Al(111) substrate are weakened by hydrogenation.
Unlike silicene, for which the demonstration of its existence has been done through numerous independent studies, possibility growing epitaxial germanene remains highly controversial. It recently shown by scanning tunneling microscopy that (3 × 3) surface reconstruction formed upon Ge deposition on Al(111) presents a honeycomb structure, and it was assigned to pure monolayer. Using quantitative measurements X-ray diffraction compared density functional theory calculations, we demonstrate...