A5021663028- Electronic and Structural Properties of Oxides
- Molecular Junctions and Nanostructures
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic properties of thin films
- Advanced Condensed Matter Physics
- Rare-earth and actinide compounds
- Magnetic and transport properties of perovskites and related materials
- Surface Chemistry and Catalysis
- Magnetism in coordination complexes
- Advanced Chemical Physics Studies
- Surface and Thin Film Phenomena
- Catalytic Processes in Materials Science
- High-pressure geophysics and materials
- Electron and X-Ray Spectroscopy Techniques
- Topological Materials and Phenomena
- ZnO doping and properties
- Copper-based nanomaterials and applications
- Hydrocarbon exploration and reservoir analysis
- Organic Electronics and Photovoltaics
- Quantum and electron transport phenomena
- Enhanced Oil Recovery Techniques
- Crystallography and Radiation Phenomena
- Graphene research and applications
- Physics of Superconductivity and Magnetism
- Porphyrin and Phthalocyanine Chemistry
Centro Brasileiro de Pesquisas Físicas
2017-2024
Brazilian Center for Research in Energy and Materials
2017-2024
University of Modena and Reggio Emilia
2004-2023
Instituto Nacional de Metrologia, Qualidade e Tecnologia
2021-2023
Ministry of Science, Technology and Innovation
2023
Brazilian Synchrotron Light Laboratory
2017-2020
Elettra-Sincrotrone Trieste S.C.p.A.
2013-2019
Universidade Federal do Rio de Janeiro
2018-2019
Hiroshima University
2018
AREA Science Park
2007-2016
We report the main characteristics of advanced photoelectric effect experiments beamline, operational at Elettra storage ring, featuring a fully independent double branch scheme obtained by use chicane undulators and able to keep polarization control in both linear circular mode. The paper describes novel technical solutions adopted, namely, (a) design quasiperiodic undulator resulting optimized suppression higher harmonics over large photon energy range (10-100 eV), (b) thermal stability...
A peculiar Rashba effect is found at a point in the Brillouin zone, where time-reversal symmetry broken, though this was believed to be necessary condition for splitting. This finding obtained experimentally by photoemission measurements on $\mathrm{Bi}/\mathrm{Si}(111)\mathrm{\text{\ensuremath{-}}}(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})$ surface fully confirmed first-principles theoretical calculation. We that simply understood two-dimensional of surface, and leads an...
Abstract We have developed a state-of-the-art apparatus for laser-based spin- and angle-resolved photoemission spectroscopy with micrometer spatial resolution (µ-SARPES). This equipment is realized by the combination of high-resolution photoelectron spectrometer, 6 eV laser high photon flux that focused down to few micrometers, high-precision sample stage control system, double very-low-energy-electron-diffraction spin detector. The setup achieves an energy 1.5 (5.5) meV without (with)...
We have measured the resonant inelastic x-ray scattering (RIXS) spectra at Cu L3 edge in a variety of cuprates. Exploiting considerably improved energy resolution (0.8 eV) we recorded significant dependencies on sample composition and orientation, geometry, incident photon polarization. The RIXS final states correspond to two families electronic excitations, having local (dd excitations) nonlocal (charge-transfer) character. dd splitting can be estimated with simple crystal field model....
The electronic and magnetic properties of cobalt-phthalocyanine (CoPc) molecules are modified at the interface with a metallic surface: upon adsorption CoPc on iron film relevant changes observed in C 1$s$ photoemission line shape Co ${L}_{2,3}$ edges, N $K$-edge x-ray absorption spectra. X-ray circular dichroism shows 3$d$ spin-polarized states, i.e., coupling substrate room temperature. interplay among sites is fundamental for tailoring functionalities hybrid organic-metallic interfaces.
Fe-phthalocyanine (FePc) molecules bonded to metal surfaces form rehybridized interface states involving the Fe central atom reflected in changes of orbital and spin configuration. X-ray absorption spectroscopy x-ray magnetic circular dichroism show ferromagnetic coupling FePc that are contact with Co(001) surface, even at room temperature (300 K), while overgrown parallel layers thicker molecular films decoupled from interface. The magnetized layer reproduces structures substrate (domains,...
In this study, we investigated the atomic-level interaction between CO molecules and a well-ordered Mn3O4(001) thin film. The oxide film, initially grown on single-crystal Au(111) substrate, was characterized using X-ray photoelectron spectroscopy (XPS) to determine its oxidation state. Further examination of film structure through scanning transmission electron microscopy (STEM) low-energy diffraction (LEED) revealed growth orientation along [001] direction, with three domains rotated by...
Novel x-ray spectroscopies such as high-resolution absorption (XAS) performed in the partial fluorescence yield mode (PFY), and resonant emission (RXES) offer new opportunities to probe bulk electronic configuration strongly correlated systems. We an Yb ${\mathrm{L}}_{3}$ PFY-XAS RXES investigation of intermediate valence compound ${\mathrm{YbAl}}_{2}$ under external pressure. found that increases from 2.25 at ambient pressure 2.9 385 kbar. This experiment has extended range pressures...
We performed bulk-sensitive x-ray absorption (XAS) in the partial fluorescence yield (PFY) mode, and resonant emission (RXES) measurements of solid solution Sc (7 at.%):$\mathrm{Ce}$ at $\mathrm{Ce}\phantom{\rule{0.3em}{0ex}}{\mathrm{L}}_{3}\phantom{\rule{0.3em}{0ex}}(2p\ensuremath{\rightarrow}5d)$ ${\mathrm{M}}_{4,5}\phantom{\rule{0.3em}{0ex}}(3d\ensuremath{\rightarrow}4f)$ edges. deduce an increasing $4f$-band hybridization from $\ensuremath{\gamma}$-phase stable room temperature to...
We studied the growth and electronic properties of Co-phthalocyanine (CoPc) molecular layers on Cu(111). Scanning tunnelling microscopy shows that CoPc molecules adsorb first at Cu(111) step edges, lying "flat", i.e., parallel to substrate. At monolayer coverage, distribute uniformly surface with short-range ordering. Angle-dependent N 1s X-ray absorption spectroscopy (XAS) confirms overall flat orientation. C 1s, core-level photoemission, Co L3 edge XAS indicate selective participation...
We present a novel additive process, which allows the spatially controlled integration of nanoparticles (NPs) inside silicon surfaces. The NPs are placed between conductive stamp and surface; by applying bias voltage SiO2 layer grows underneath protrusions, thus embedding particles. report successful nanoembedding CoFe2O4 patterned in lines, grids logic structures.
The charge state of Au nanoparticles deposited on MgO/Fe(001) ultrathin films has been investigated experimentally by means X-ray photoemission spectroscopy and theoretically performing density functional theory (DFT) calculations. binding energy the 4f7/2 core-level peak studied as a function coverage MgO film thickness. presents high value (about 600 meV higher than that bulk Au) for smallest thick films. shift is only 200 particles very thin films, indicating different electronic...
Abstract A proper understanding on the charge mobility in organic materials is one of key factors to realize highly functionalized semiconductor devices. So far, however, although a number studies have proposed carrier transport mechanism rubrene single crystal be band-like, there are disagreements between results reported these papers. Here, we show that actual dispersion widths electronic bands formed by highest occupied molecular orbital much smaller than those literature, and originate...
We present a resonant x-ray emission study of the pressure-induced valence transition $\mathrm{SmS}$. Spectra excited at ${L}_{3}$ absorption edge Sm ions were recorded applied pressures ranging from 1 to $18\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, room temperature. Thanks its extreme sensitivity electronic configuration, inelastic is well suited follow precisely small changes in high pressure region. The found increase 2.7 $1\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ 3 and trivalent state...
We present a comprehensive study of the photon energy dependence valence band photoemission yield in prototype Mott-Hubbard oxide ${\text{V}}_{2}{\text{O}}_{3}$. The analysis our experimental results, covering an extended range (20--6000 eV) and combined with GW calculations, allows us to identify nature orbitals contributing total spectral weight at different binding energies, particular locate $\text{V}\text{ }4s$ states about 8 eV energy. From this comparative analysis, we conclude that...
We present a combined experimental and theoretical study of the ultrathin film Co-octaethylporphyrin (Co-OEP) molecules deposited on Ag(110) surface. The morphological electronic properties this heterogeneous metallorganic interface were studied by means scanning tunneling microscopy (STM), near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, ultraviolet photoemission spectroscopy (UPS), density functional theory calculations (DFT). long-range self-ordered single layer Co-OEP was...
Pentacene adsorbed on the Cu(119) vicinal surface forms long-range ordered chain structures. Photoemission spectroscopy measurements and ab initio density functional theory simulations provide consistent evidences that pentacene molecular orbitals mix with copper bands, giving rise to interaction states localized at interface. Angular-resolved polarization dependent photoemission shows most of derived intensity is strongly dichroic. The symmetry free molecules reduced upon adsorption...
We have grown the phase-homogeneous ternary compound with composition ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{1.85}{\mathrm{S}}_{1.15}$ very close to stoichiometric ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{2}\mathrm{S}$. The measurements performed spin- and angle-resolved photoelectron spectroscopy as well density functional theory $GW$ calculations revealed a wide-band-gap three-dimensional topological insulator phase. surface electronic spectrum is characterized by state (TSS) Dirac point located above...
A totally anisotropic peculiar Rashba-Bychkov (RB) splitting of electronic bands was found on the Tl/Si(110)-(1×1) surface with C_{1h} symmetry by angle- and spin-resolved photoelectron spectroscopy first-principles theoretical calculation. The constant energy contour upper branch RB split band has a warped elliptical shape centered at k point located between Γ[over ¯] edge Brillouin zone, i.e., without time-reversal symmetry. spin-polarization vector this state is in-plane points almost...
Abstract Hydrotalcite‐based materials are preferred as catalysts due to their versatility and easiness of synthesis. This work studies supported nickel made from hydrotalcites through sol‐gel synthesis, Ni‐EDTA impregnation, coprecipitation. The synthetized present nanocapsular morphology dispersed nano‐oxide particles after calcination at 500 °C. were evaluated 600 °C 800 for 8 hours demonstrated high conversions varying yields, with oxide (Sg OxMix ) showing the best performance highest...
This study offers valuable insights into the precipitation behavior of 13Ni maraging steels, emphasizing role molybdenum content in their microstructure, strengthening, and precipitate evolution. Precipitate morphology crystallography were examined using a combination high-resolution transmission electron microscopy selected area diffraction. Strengthening mechanisms assessed through Vickers hardness measurements. All samples exhibited lath martensite microstructure displayed an increasing...