773 research outputs found

    Coherent and incoherent bands in La and Rh doped Sr3Ir2O7

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    In Sr2IrO4 and Sr3Ir2O7, correlations, magnetism and spin-orbit coupling compete on similar energy scales, creating a new context to study metal-insulator transitions (MIT). We use here Angle-Resolved photoemission to investigate the MIT as a function of hole and electron doping in Sr3Ir2O7, obtained respectively by Ir/Rh and Sr/La substitutions. We show that there is a clear reduction as a function of doping of the gap between a lower and upper band on both sides of the Fermi level, from 0.2eV to 0.05eV. Although these two bands have a counterpart in band structure calculations, they are characterized by a very different degree of coherence. The upper band exhibits clear quasiparticle peaks, while the lower band is very broad and loses weight as a function of doping. Moreover, their ARPES spectral weights obey different periodicities, reinforcing the idea of their different nature. We argue that a very similar situation occurs in Sr2IrO4 and conclude that the physics of the two families is essentially the same

    Giant Anisotropy of Spin-Orbit Splitting at the Bismuth Surface

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    We investigate the bismuth (111) surface by means of time and angle resolved photoelectron spectroscopy. The parallel detection of the surface states below and above the Fermi level reveals a giant anisotropy of the Spin-Orbit (SO) spitting. These strong deviations from the Rashba-like coupling cannot be treated in kp\textbf{k}\cdot \textbf{p} perturbation theory. Instead, first principle calculations could accurately reproduce the experimental dispersion of the electronic states. Our analysis shows that the giant anisotropy of the SO splitting is due to a large out-of plane buckling of the spin and orbital texture.Comment: 5 pages, 4 figure

    Ultrafast filling of an electronic pseudogap in an incommensurate crystal

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    We investigate the quasiperiodic crystal (LaS)1.196(VS2) by angle and time resolved photoemission spectroscopy. The dispersion of electronic states is in qualitative agreement with band structure calculated for the VS2 slab without the incommensurate distortion. Nonetheless, the spectra display a temperature dependent pseudogap instead of quasiparticles crossing. The sudden photoexcitation at 50 K induces a partial filling of the electronic pseudogap within less than 80 fs. The electronic energy flows into the lattice modes on a comparable timescale. We attribute this surprisingly short timescale to a very strong electron-phonon coupling to the incommensurate distortion. This result sheds light on the electronic localization arising in aperiodic structures and quasicrystals

    Transfer of spectral weight across the gap of Sr2IrO4 induced by La doping

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    We study with Angle Resolved PhotoElectron Spectroscopy (ARPES) the evolution of the electronic structure of Sr2IrO4, when holes or electrons are introduced, through Rh or La substitutions. At low dopings, the added carriers occupy the first available states, at bottom or top of the gap, revealing an anisotropic gap of 0.7eV in good agreement with STM measurements. At further doping, we observe a reduction of the gap and a transfer of spectral weight across the gap, although the quasiparticle weight remains very small. We discuss the origin of the in-gap spectral weight as a local distribution of gap values

    Significant reduction of electronic correlations upon isovalent Ru substitution of BaFe2As2

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    We present a detailed investigation of Ba(Fe0.65Ru0.35)2As2 by transport measurements and Angle Resolved photoemission spectroscopy. We observe that Fe and Ru orbitals hybridize to form a coherent electronic structure and that Ru does not induce doping. The number of holes and electrons, deduced from the area of the Fermi Surface pockets, are both about twice larger than in BaFe2As2. The contribution of both carriers to the transport is evidenced by a change of sign of the Hall coefficient with decreasing temperature. Fermi velocities increase significantly with respect to BaFe2As2, suggesting a significant reduction of correlation effects. This may be a key to understand the appearance of superconductivity at the expense of magnetism in undoped iron pnictides

    A hospital incident reporting system (2016-2019) : Learning from notifier's perception on incidents'risk, severity and frecuency of adverse events

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    Incident reporting systems (IRSs) are considered safety culture promoters. Nevertheless, they have not been contemplated to monitor professionals' perception about patient safety related risks. This study aims to describe the characteristics and evolution of incident notifications reported between 2016 and 2019 in a high complexity reference hospital in Barcelona and explores the association between notifications' characteristics and notifier's perception about incidents severity, probability of occurrence and risk. The main analysis unit was notifications reported. A descriptive analysis was performed and taxes by hospital activity were calculated. Odds ratios were obtained to study the association between the type of incident, the moment of incident, notifiers' professional category, reported incident's severity, probability and incidents' calculated risk. Through the study period, a total of 6379 notifications were reported, observing an annual increase of notifications until 2018. Falls (21.22%), Medical and procedures management (18.91%) and Medication incidents (15.49%) were the most frequently notified. Departments reporting the highest number of notifications were Emergency room and Obstetrics & Gynaecology. Incident type and notifiers' characteristics were consistently included in the models constructed to assess risk perception. Pharmaceutics were the most frequent notifiers when considering the proportion of staff members. Notification patterns can inform professionals' patient risk perception and increase awareness of professionals' misconceptions regarding patient safety
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