Publications de Marco Grioni | EPFL Graph Search

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We demonstrate a giant Rashba-type spin splitting on a semiconducting substrate by means of a Bi-trimer adlayer on a Si(111) wafer. The in-plane inversion symmetry is broken inducing a giant spin splitting with a Rashba energy of about 140 meV, much larger ...

We present a 5 m long spectrometer for soft x rays to be used at a synchrotron radiation beamline for resonant x-ray emission spectroscopy and resonant inelastic x-ray scattering in the 400-1600 eV energy range. It is based on a variable line spacing spher ...

Using low-energy projection of the one-band t-t′-t′′ Hubbard model we derive an effective spin Hamiltonian and its spin-wave expansion to order 1/S. We fit the spin-wave dispersion of several parent compounds to the high-temperature superconducting cuprate ...

Novel x-ray spectroscopies such as high-resolution x-ray absorption (XAS) performed in the partial fluorescence yield mode (PFY), and resonant emission (RXES) offer new opportunities to probe the bulk electronic configuration in strongly correlated systems. We performed an Yb L-3 PFY-XAS and RXES investigation of the intermediate valence compound YbAl2 under external pressure. We found that the Yb valence increases from 2.25 at ambient pressure to 2.9 at 385 kbar. This experiment has extended the range of p

Bilayer graphene is a highly promising material for electronic and optoelectronic applications since it is supporting massive Dirac fermions with a tunable band gap. However, no consistent picture of the gap's effect on the optical and transport behavior h ...

The long-range ordered surface alloy Bi/Ag(111) is found to exhibit a giant spin splitting of its surface electronic structure due to spin-orbit coupling, as is determined by angle-resolved photoelectron spectroscopy. First-principles electronic structure ...

The prediction of Weyl fermions in the low-temperature noncentrosymmetric 1T' phase of MoTe2 still awaits clear experimental confirmation. Here, we report angle-resolved photoemission (ARPES) data and ab initio calculations that reveal a surface state arc ...

Describing the nanoscale charge carrier transport at surfaces and interfaces is fundamental for designing highperformance optoelectronic devices. To achieve this, we employ time-and angle-resolved photoelectron spectroscopy with ultraviolet pump and extrem ...

Photoelectron spectroscopy reveals a striking correspondence between charge-density-wave-related phase transitions and modifications of the electronic structure in 1T-TaS2. High-energy-resolution spectra indicate that the collapse of the Fermi surface is abrupt at the quasicommensurate-commensurate transition (approximately 185 K) and that, below this critical temperature, the Fermi level lies in a deep, temperature-dependent pseudogap. These results strongly suggest successive localizations due to electron

The prospect of optically inducing and controlling a spin-polarized current in spintronic devices has generated wide interest in the out-of-equilibrium electronic and spin structure of topological insulators. In this Letter we show that only measuring the ...

We performed bulk-sensitive x-ray absorption (XAS) in the partial fluorescence yield (PFY) mode, and resonant x-ray emission (RXES) measurements of the solid solution Sc (7 at.%):Ce at the Ce L-3 (2p-->5d) and M-4,M-5 (3d-->4f) absorption edges. We deduce an increasing 4f-band hybridization from the gamma-phase stable at room temperature to the low-temperature alpha-Ce, consistent with the "Kondo collapse" scenario for the transition. The enhanced intrinsic resolution of PFY-XAS allows us to resolve the elu

Dispersing 1D bands have been observed for the first time in an organic conductor by high resolution photoemission experiments on TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane). Their properties are extremely unusual: the bandwidth is much larger than traditional estimates, and the quasiparticle states are strongly renormalized, with no weight at the chemical potential. A deep pseudogap around the Fermi energy persists, and even increases, up to room temperature. We also report a direct determinatio

In this Letter we report the observation, by scanning tunneling microscopy, of a Mott metal to insulator transition at the surface of 1T-TaSe2. Our spectroscopic data compare considerably well with previous angle-resolved photoemission spectroscopy measure ...

In this paper we review the present status of electron spectroscopy of Ce and Yb Kondo systems, with particular emphasis on photoemission and inverse photoemission. Our starting point is the situation in the mid-1980s, characterized by the development of a 'Kondo scenario' for the thermodynamic and spectral properties, as described in the review by Allen et al. (1986, Adv. Phys., 35, 275). That picture, based on room-temperature results and on a T=0 approach to the impurity Anderson Hamiltonian, has been ge

The instrument VOLPE (volume photoemission from solids) is an experimental setup dedicated to high energy photoemission (PE) experiments. The instrument is equipped with an electrostatic hemispherical spectrometer especially designed to analyze high energy ...

Intermediate valence is one of the typical phenomena of systems with strong electronic correlation. The Anderson impurity model predicts a scaling of the valence with the reduced temperature T/T-K, which is difficult to observe by traditional surface-sensitive electronic spectroscopies. This paper presents results obtained by resonant inelastic X-ray scattering (RIXS), a bulk-sensitive configuration- and chemical-specific technique. The temperature dependence of the valence of YbInCu4 and YbAgCu4 was measur

Superconductivity in high-Tc cuprates is particularly sensitive to disorder due to the unconventional d-wave pairing symmetry. We investigated effects of disorder on the spectral properties of Bi2Sr2CaCu2O8+x high-Tc superconductor. We found that already small defect densities suppress the characteristic spectral signature of the superconducting state. The spectral line shape clearly reflects new excitations within the gap, as expected for de

With its tunable band-gap and its unique optical and electronic properties black phosphorus (BP) opens exciting opportunities for optoelectronic nanotechnology. The band-gap extends from the visible to the mid-infrared spectral range, as a function of samp ...

The structural and electronic properties of a Pb monolayer (ML) grown on Au(111) are investigated by scanning tunneling microscopy (STM) and angle resolved photoelectron spectroscopy (ARPES). We find an incommensurate Moire structure with an approximate (5 ...

The influence of dimensionality on the electronic properties of layered perovskite materials remains an outstanding issue. We address it here for Sr3Ir2O7, the bilayer compound of the iridate Srn+1IrnO3n+1 series. By angle-resolved photoemission spectroscopy we show that in this material the interlayer coupling is large and that the intercell coupling is, conversely, negligible. From a detailed mapping of the bilayer splitting, and from the intensity modulation of the bonding and antibonding bands with phot

Marco Grioni

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Silicon Surface with Giant Spin Splitting

SAXES, a high resolution spectrometer for resonant x-ray emission in the 400-1600 eV energy range

Unified one-band Hubbard model for magnetic and electronic spectra of the parent compounds of cuprate superconductors

Determination of pressure-induced valence changes in YbAl2 by resonant inelastic x-ray emission

Ultrafast Dynamics of Massive Dirac Fermions in Bilayer Graphene

Giant spin splitting through surface alloying

Persistence of a surface state arc in the topologically trivial phase of MoTe2

Nanoscale-Resolved Surface-to-Bulk Electron Transport in CsPbBr3 Perovskite

Temperature-Dependent Pseudogap And Electron Localization In 1T-Tas2

Momentum-Resolved Spin Dynamics of Bulk and Surface Excited States in the Topological Insulator Bi2Se3

alpha-gamma transition in metallic Ce studied by resonant x-ray spectroscopies

Band mapping and quasiparticle suppression in the one-dimensional organic conductor TTF-TCNQ

Mott phase at the surface of 1T-TaSe2 observed by scanning tunneling microscopy

Recent developments in high-energy spectroscopies of Kondo systems

Experimental setup for high energy photoemission using synchrotron radiation

Truly bulk-sensitive spectroscopic measurements of valence in heavy fermion materials

Defect-induced changes in the spectral properties of high-Tc cuprates

Photocarrier-induced band-gap renormalization and ultrafast charge dynamics in black phosphorus

Combined ARPES and STM study of Pb/Au(111) Moiré structure: One overlayer, two symmetries

Bilayer splitting and wave functions symmetry in Sr3Ir2O7