A5024555740- 2D Materials and Applications
- Topological Materials and Phenomena
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- Orbital Angular Momentum in Optics
- Electronic and Structural Properties of Oxides
- Physics of Superconductivity and Magnetism
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- Magneto-Optical Properties and Applications
- Graphene research and applications
- Multiferroics and related materials
- Quantum and electron transport phenomena
- Photocathodes and Microchannel Plates
- Advanced Electron Microscopy Techniques and Applications
- Molecular spectroscopy and chirality
- Advanced Chemical Physics Studies
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Inorganic Chemistry and Materials
- Advanced X-ray Imaging Techniques
- Rare-earth and actinide compounds
- Phase-change materials and chalcogenides
- Solar and Space Plasma Dynamics
- Crystallization and Solubility Studies
Laboratoire Interactions, Dynamiques et Lasers
2020-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2020-2024
CEA Paris-Saclay
2020-2024
CY Cergy Paris Université
2019-2024
Université Paris-Saclay
2020-2024
Centre National de la Recherche Scientifique
2020-2023
University of Nova Gorica
2023
Elettra-Sincrotrone Trieste S.C.p.A.
2023
École Polytechnique Fédérale de Lausanne
2017-2020
Paul Scherrer Institute
2016-2020
Abstract Magneto-optical (MO) effects, viz. magnetically induced changes in light intensity or polarization upon reflection from transmission through a magnetic sample, were discovered over century and half ago. Initially they played crucially relevant role unveiling the fundamentals of electromagnetism quantum mechanics. A more broad-based relevance wide-spread use MO methods, however, remained quite limited until 1960s due to lack suitable, reliable easy-to-operate sources. The advent...
Spin- and angle-resolved photoemission spectroscopy is used to reveal that a large spin polarization observable in the bulk centrosymmetric transition metal dichalcogenide MoS2. It found measured can be reversed by changing handedness of incident circularly-polarized light. Calculations based on three-step model show valley layer-locked spin-polarized electronic states selectively addressed light, therefore providing novel route probe these hidden inversion-symmetric systems as predicted...
Abstract Entanglement of the spin–orbit and magnetic order in multiferroic materials bears a strong potential for engineering novel electronic spintronic devices. Here, we explore electron spin structure ferroelectric α -GeTe thin films doped with ferromagnetic Mn impurities to achieve its functionality. We use bulk-sensitive soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES) follow hybridization GeTe valence band dopants. observe gradual opening Zeeman gap bulk Rashba bands...
Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of chiral crystal. We have studied by spin- angle-resolved photoelectron spectroscopy its unconventional electronic structure unique spin texture. identify Kramers-Weyl, composite, accordionlike Weyl fermions, so far only predicted theory, show that polarization parallel to wave vector along lines in k space connecting high-symmetry points. Our...
Electromagnetic waves possessing orbital angular momentum (OAM) are powerful tools for applications in optical communications, quantum technologies, and tweezers. Recently, they have attracted growing interest since can be harnessed to detect peculiar helical dichroic effects chiral molecular media magnetic nanostructures. In this work, we perform single-shot per position ptychography on a nanostructured object at seeded free-electron laser, using extreme ultraviolet OAM beams of different...
We report on the experimental evidence of magnetic helicoidal dichroism, observed in interaction an extreme ultraviolet vortex beam carrying orbital angular momentum with a vortex. Numerical simulations based classical electromagnetic theory show that this dichroism is interference light modes different momenta, which are populated after between and topology. This observation gives insight into interplay magnetism sets framework for development new analytical tools to investigate ultrafast...
The control of the electron spin by external means is a key issue for spintronic devices. Using spin- and angle-resolved photoemission spectroscopy (SARPES) with three-dimensional detection, we demonstrate operando electrostatic manipulation in ferroelectric GeTe multiferroic Ge1-xMnxTe. We not only first time Rashba semiconductors due to polarization reversal, but are also able follow switching pathway detail, show gain Rashba-splitting strength under fields. In Ge1-xMnxTe SARPES reveals...
Few-layer thick MoSe2 and WSe2 possess non-trivial spin textures with sizable splitting due to the inversion symmetry breaking embedded in crystal structure strong spin-orbit coupling. We report a spin-resolved photoemission study of thin film samples epitaxially grown on bilayer graphene substrate. only found polarization single- trilayer samples-not sample-mostly along out-of-plane direction sample surface. The measured is be strongly dependent light as well measurement geometry, which...
After photon absorption, electrons from a dispersive band of solid require finite time in the photoemission process before being photoemitted as free particles, line with recent attosecond-resolved experiments. According to Eisenbud-Wigner-Smith model, delay is due phase shift different transitions that occur process. Such also at origin angular dependent spin polarization photoelectron beam, observable degenerate systems without momentum transfer by incident photon. We propose...
We present the classical electromagnetic theory framework of reflection a light beam carrying orbital angular momentum (OAM) by magnetic structure with generic symmetry. Depending on magnetization symmetry, we find change in OAM content reflected due to magneto-optic interaction and an asymmetric far-field intensity profile. This leads three types helicoidal dichroism (MHD), observed when switching incoming beam, sign, or both. In cases sufficient symmetries, such as domain walls vortices,...
Monolayer structures of Pb on Si(111) attracted recently considerable interest as superconductivity was found in these truly two-dimensional (2D) structures. In this study, we analyzed the electronic surface band structure so-called striped incommensurate phase with $\frac{4}{3}$ ML coverage by means spin-resolved photoemission spectroscopy. Our results fully agree density functional theory calculations done Ren et al. [Phys. Rev. B 94, 075436 (2016)]. We observe a local Zeeman-type...
The authors present spin, time, and angle resolved photoemission spectroscopy measurements on the transition metal dichalcogenide bulk WTe2. results show a response of spin polarization in unoccupied states above proposed Weyl type-II points region. observed accumulation after pump pulse is interpreted as spin-selective bottleneck effect, consistent with presence polarized cone-like electronic structure independent topological classification
The semimetal ${\mathrm{MoTe}}_{2}$ is studied by spin- and angle-resolved photoemission spectroscopy across the centrosymmetry-breaking structural transition temperature of bulk. A three-dimensional spin-texture observed in bulk Fermi surface low temperature, noncentrosymmetric phase that consistent with first-principles calculations. spin texture two types arc are not completely suppressed above temperature. lifetimes quasiparticles forming arcs depend on thermal history lengthen...
Ferroelectric $\ensuremath{\alpha}$-GeTe is unveiled to exhibit an intriguing multiple nontrivial topology of the electronic band structure due existence triple-point and type-II Weyl fermions, which goes well beyond giant Rashba spin splitting controlled by external fields as previously reported. Using spin- angle-resolved photoemission spectroscopy combined with ab initio density functional theory, unique texture around triple point caused crossing one spin-degenerate two spin-split bands...
The potential of resonant inelastic soft x-ray scattering to measure $4f$ crystal electric-field excitation spectra in Ce Kondo lattices has been examined. Spectra have obtained for several systems and show a well-defined structure determined by crystal-field, spin-orbit, charge-transfer excitations only. spectral shapes the can be well understood framework atomic multiplet calculations. For ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$ we found notable disagreement between x-ray-scattering...
This paper uses light polarization dependent spin-resolved photoemission and ab initio calculations to show that bulk states of ferroelectric GeTe are fully spin polarized, making this material a promising candidate for room temperature spintronics applications.
The discovery of Weyl semimetals represents a significant advance in topological band theory. They paradigmatically enlarged the classification materials to gapless systems while simultaneously providing experimental evidence for long-sought fermions. Beyond fundamental relevance, their high mobility, strong magnetoresistance, and possible existence even more exotic effects, such as chiral anomaly, make promising platform develop radically new technology. Fully exploiting potential requires...
The dosing of layered materials with alkali metals has become a commonly used strategy in ARPES experiments. However, precisely what occurs under such conditions, both structurally and electronically, remained matter debate. Here we perform systematic study 1T-HfTe$_2$, prototypical semimetal the transition metal dichalcogenide family. By utilizing photon energy-dependent angle-resolved photoemission spectroscopy (ARPES), have investigated electronic structure this material as function...
The $\ensuremath{\alpha}$-Sn reconstruction on Si(111) is a prototype system for two-dimensional Mott phase. In this study we performed spin-resolved photoemission experiments and analyzed in detail the spin structure of electronically correlated surface state. analysis spin-integrated bands as well texture states along different crystallographic directions provide clear evidence formation collinear antiferromagnetic $(2\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})$ domains, while Sn...
Observation of Bloch oscillations and Wannier-Stark localization charge carriers is typically impossible in single-crystals, because an electric field higher than the breakdown voltage required. In BaTiO$_3$ however, high intrinsic fields are present due to its ferroelectric properties. With angle-resolved photoemission we directly probe localized surface states film-vacuum interface show that this effect extends thin SrTiO$_3$ overlayers. The electrons found be along in-plane polarization...
This work investigates a two dimensional electron gas formed on the surface of nominally insulating SrTiO${}_{3}$ thin films grown Nb-doped substrates. The authors show that, for particular Nb concentration, system presents single spin-polarized Fermi surface.