Fate of Quasiparticles at High Temperature in the Correlated Metal Sr_{2}RuO_{4}

We study the temperature evolution of quasiparticles in the correlated metal Sr_{2}RuO_{4}. Our angle resolved photoemission data show that quasiparticles persist up to temperatures above 200 K, far beyond the Fermi liquid regime. Extracting the quasiparticle self-energy, we demonstrate that the quasiparticle residue Z increases with increasing temperature. Quasiparticles eventually disappear on approaching the bad metal state of Sr_{2}RuO_{4} not by losing weight but via excessive broadening from super-Planckian scattering. We further show that the Fermi surface of Sr_{2}RuO_{4}-defined as the loci where the spectral function peaks-deflates with increasing temperature. These findings are in semiquantitative agreement with dynamical mean field theory calculations.

Antiferromagnetic topological insulator with selectively gapped Dirac cones

Antiferromagnetic (AF) topological materials offer a fertile ground to explore a variety of quantum phenomena such as axion magnetoelectric dynamics and chiral Majorana fermions. To realize such intriguing states, it is essential to establish a direct link between electronic states and topology in the AF phase, whereas this has been challenging because of the lack of a suitable materials platform. Here we report the experimental realization of the AF topological-insulator phase in NdBi. By using micro-focused angle-resolved photoemission spectroscopy, we discovered contrasting surface electronic states for two types of AF domains; the surface having the out-of-plane component in the AF-ordering vector displays Dirac-cone states with a gigantic energy gap, whereas the surface parallel to the AF-ordering vector hosts gapless Dirac states despite the time-reversal-symmetry breaking. The present results establish an essential role of combined symmetry to protect massless Dirac fermions under the presence of AF order and widen opportunities to realize exotic phenomena utilizing AF topological materials.

Flat Γ Moiré Bands in Twisted Bilayer WSe_{2}

The recent observation of correlated phases in transition metal dichalcogenide moiré systems at integer and fractional filling promises new insight into metal-insulator transitions and the unusual states of matter that can emerge near such transitions. Here, we combine real- and momentum-space mapping techniques to study moiré superlattice effects in 57.4° twisted WSe_{2} (tWSe_{2}). Our data reveal a split-off flat band that derives from the monolayer Γ states. Using advanced data analysis, we directly quantify the moiré potential from our data. We further demonstrate that the global valence band maximum in tWSe_{2} is close in energy to this flat band but derives from the monolayer K states which show weaker superlattice effects. These results constrain theoretical models and open the perspective that Γ-valley flat bands might be involved in the correlated physics of twisted WSe_{2}.

Improved electron trajectory and power distribution in APPLE-knot undulator

The APPLE-Knot undulator has been proposed to reduce the large on-axis heat load of the APPLE-II at very low photon energy. However, the current designs have an inherent non-zero second field integral due to the Knot sections, resulting in a transverse deflection of the electron beam throughout the undulator. For a long device, such a deviation can degrade the brightness and power distribution of the outgoing beam. Here, a new end-Knot section is presented to compensate for the electron trajectory, and the undulator is symmetrized to balance the output power distribution. The performance of the APPLE-Knot with symmetric power distribution is investigated. The partial power, flux, and polarization are compared with the APPLE-II. In the linear mode, APPLE-Knot shows a pronounced reduction of the partial power, with a similar flux to the APPLE-II. The symmetric power density distribution reduces the hotspot by 41%, with a flux loss of less than 5%. In the circular mode and at low photon energies, the flux is limited by the phase error of the symmetric design.

Observation of topological superconductivity in a stoichiometric transition metal dichalcogenide 2M-WS2

Topological superconductors (TSCs) are unconventional superconductors with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for quantum computation. Despite their importance in both fundamental research and applications, natural TSCs are very rare. Here, combining state of the art synchrotron and laser-based angle-resolved photoemission spectroscopy, we investigated a stoichiometric transition metal dichalcogenide (TMD), 2M-WS₂ with a superconducting transition temperature of 8.8 K (the highest among all TMDs in the natural form up to date) and observed distinctive topological surface states (TSSs). Furthermore, in the superconducting state, we found that the TSSs acquired a nodeless superconducting gap with similar magnitude as that of the bulk states. These discoveries not only evidence 2M-WS₂ as an intrinsic TSC without the need of sensitive composition tuning or sophisticated heterostructures fabrication, but also provide an ideal platform for device applications thanks to its van der Waals layered structure.

Orbital Complexity in Intrinsic Magnetic Topological Insulators MnBi_{4}Te_{7} and MnBi_{6}Te_{10}

Using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of the magnetic van der Waals compounds MnBi_{4}Te_{7} and MnBi_{6}Te_{10}, the n=1 and 2 members of a modular (Bi_{2}Te_{3})_{n}(MnBi_{2}Te_{4}) series, which have attracted recent interest as intrinsic magnetic topological insulators. Combining circular dichroic, spin-resolved and photon-energy-dependent ARPES measurements with calculations based on density functional theory, we unveil complex momentum-dependent orbital and spin textures in the surface electronic structure and disentangle topological from trivial surface bands. We find that the Dirac-cone dispersion of the topologial surface state is strongly perturbed by hybridization with valence-band states for Bi_{2}Te_{3}-terminated surfaces but remains preserved for MnBi_{2}Te_{4}-terminated surfaces. Our results firmly establish the topologically nontrivial nature of these magnetic van der Waals materials and indicate that the possibility of realizing a quantized anomalous Hall conductivity depends on surface termination.

Magnetic Weyl semimetal phase in a Kagomé crystal

Weyl semimetals are crystalline solids that host emergent relativistic Weyl fermions and have characteristic surface Fermi-arcs in their electronic structure. Weyl semimetals with broken time reversal symmetry are difficult to identify unambiguously. In this work, using angle-resolved photoemission spectroscopy, we visualized the electronic structure of the ferromagnetic crystal Co₃Sn₂S₂ and discovered its characteristic surface Fermi-arcs and linear bulk band dispersions across the Weyl points. These results establish Co₃Sn₂S₂ as a magnetic Weyl semimetal that may serve as a platform for realizing phenomena such as chiral magnetic effects, unusually large anomalous Hall effect and quantum anomalous Hall effect.

Bulk and Surface Electronic Structure of the Dual-Topology Semimetal Pt_{2}HgSe_{3}

We report high-resolution angle-resolved photoemission measurements on single crystals of Pt_{2}HgSe_{3} grown by high-pressure synthesis. Our data reveal a gapped Dirac nodal line whose (001) projection separates the surface Brillouin zone in topological and trivial areas. In the nontrivial k-space range, we find surface states with multiple saddle points in the dispersion, resulting in two van Hove singularities in the surface density of states. Based on density-functional theory calculations, we identify these surface states as signatures of a topological crystalline state, which coexists with a weak topological phase.

Photoemission from non-polar aromatic molecules in the gas and liquid phase

The photoelectron spectra of both liquid and gas phase aromatic molecules are reported. The spectra were obtained using a 34.1 eV source produced by high harmonic generation and analysed with the help of high-level ab initio simulations using the reflection principle combined with path integral molecular dynamics simulations accounting for nuclear quantum effects for the gas phase. We demonstrate the suitability of three trimethylbenzenes (1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene and 1,2,4-trimethylbenzene) as a solvent for liquid photoelectron spectroscopy of solute species. We also discuss the electrokinetic charging of a non-polar liquid jet.

Ab initio simulations and measurements of the free-free opacity in aluminum

The free-free opacity in dense systems is a property that both tests our fundamental understanding of correlated many-body systems, and is needed to understand the radiative properties of high energy-density plasmas. Despite its importance, predictive calculations of the free-free opacity remain challenging even in the condensed matter phase for simple metals. Here we show how the free-free opacity can be modelled at finite-temperatures via time-dependent density functional theory, and illustrate the importance of including local field corrections, core polarization, and self-energy corrections. Our calculations for ground-state Al are shown to agree well with experimental opacity measurements performed on the Artemis laser facility across a wide range of extreme ultraviolet wavelengths. We extend our calculations across the melt to the warm-dense matter regime, finding good agreement with advanced plasma models based on inverse bremsstrahlung at temperatures above 10 eV.

P1520Management and outcome of women with NSTEMI. Have there been any changes in recent years?

Introduction

Women have been less represented in every NSTEMI clinical trial. Moreover, it has been observed that this group of patients have usually received less revascularization and evidence based treatment, therefore presenting with a greater long and short-term mortality.

Purpose

The purpose of our study is to analyze the presence of differences in baseline characteristics, management and outcome of women with NSTEMI during the last decade.

Methods and results

Retrospective study including 861 women admitted for NSTEMI between 2003 and 2015 in our center. We divided 2 groups according to hospitalization period (2003–2008 and 2009–2015) with a medium follow up of 4.5±2.9 years. Baseline characteristics and treatment at discharge are described on table 1. We noticed a greater use of statins and ACEI/ARB on the second period as well as a greater percentage of patients receiving early revascularization. It is remarkable on women a non-significant reduction of heart failure hospitalization at follow up (6.8% vs 4.5%; p=0.091), neither differences on 30-day mortality (1.3% vs 0,4%) or 1-year mortality (7.1% vs 5.8%). However, long-term mortality for the second group is reduced (HR 0.69; CI 95% 0.52–0.89), even after performing a multivariate analysis (HR 0.64; CI 95% 0.48–0.85).

Characteristic Population (n=861) 2003–2008 (n=395) 2009–2015 (n=466) p-value Age (years) 73±12 73±12 72±12 0.316 Hypertension 629 (73.1%) 285 (72.2%) 344 (73.8%) 0.318 Hypercholesterolemia 414 (48.1%) 190 (48.1%) 224 (48.1%) 0.523 Killip class 0.292   I 664 (77.1%) 299 (75.7%) 365 (78.3%)   II 143 (16.6%) 74 (18.7%) 69 (14.8%)   III 47 (5.5%) 20 (5.1%) 27 (5.8%)   IV 4 (0.5%) 2 (0.5%) 2 (0.4) GRACE score 129±32 130±37 128±33 0.897 Early PCI 249 (29.3%) 76 (19.2%) 173 (38.0%) <0.005 Treatment at discharge   AAS 698 (81.1%) 313 (79.2%) 385 (82.6%) 0.120   Clopidogrel 465 (54.0%) 221 (55.9%) 244 (52.4%) 0.162   ACEI/ARB 466 (54.1%) 191 (48.4%) 275 (59.0%) 0.001   Beta-blocker 509 (59.1%) 238 (60.3%) 271 (58.2%) 0.290   Statins 643 (74.7%) 275 (69.6%) 368 (79.0%) 0.001

Conclusions

In recent years, early interventionist management and greater use of evidence-based therapies have been observed in women with NSTEMI. This has been associated with a lesser long-term mortality, although short-term events have remained the same.

P1560Prognostic predictors of mortality in very elderly patients presenting with NSTEMI

Background

Elderly patients are usually under-represented in randomized controlled trials, therefore there is less data providing prognostic information for this particular group. NSTEMI clinical practice guidelines indicate that older patients should receive the same therapeutic strategy than younger patients.

Methods

Observational retrospective study including 8771 patients admitted for acute coronary syndrome in two tertiary referral hospitals between 2003 and 2017: 5673 NSTEMI (64.3%) and 3098 STEMI (35.7%). 999 patients presenting with NSTEMI and aged over 75 years were selected and divided into 3 groups: aged 75–80, aged 80–89 and aged over 90. Cox proportional hazard regression analysis was performed in order to determine independent predictors of mortality. Mortality and survival were represented by Kaplan-Meier curves and log rank test was conducted to assess significant differences in survival between groups. Median follow-up period was 48 months.

Results

A significant association between female sex and elder age was observed, also a higher prevalence of hyperlipemia and diabetes. In acute phase, no significant differences were found in between congestive heart failure onset, myocardial re-infarction, acute renal failure, stroke or in-hospital mortality amongst the 3 groups. However, at follow-up period, higher mortality in elder groups was documented. After performing a multivariate analysis, age was identified as an independent predictor of mortality at follow-up (<90 years: HR 1.50 CI 95% 1.23–1.83, p=0.0001, >90 years: HR 1.93 CI 95% 1.27–2.93, p=0.002) as well as GRACE score (HR 1.06, CI 95% 1.02–1.09, p=0.002), CRUSADE score (HR 1.01 CI 95% 1.01–1.02, p=0.0001) and treatment with digoxine (HR 1.38 CI 95% 0.95–2.0, p=0.08). On the other side, beta-blockers (HR 0.71 CI 95% 0.59–0.86, p=0.0001) and complete coronary revascularization (HR 0.48 CI 95% 0.37–0.64, p=0.0001) were found to be protective factors.

Conclusions

In very elderly patients presenting with NSTEMI, prognostic predictors of mild-term mortality are similar to those present in younger patients. Recommendations of clinical practice guidelines, such as beta-blockers' treatment and coronary revascularization, should also be applied in elderly patients.

Distinctive Picosecond Spin Polarization Dynamics in Bulk Half Metals

Femtosecond laser excitations in half-metal (HM) compounds are theoretically predicted to induce an exotic picosecond spin dynamics. In particular, conversely to what is observed in conventional metals and semiconductors, the thermalization process in HMs leads to a long living partially thermalized configuration characterized by three Fermi-Dirac distributions for the minority, majority conduction, and majority valence electrons, respectively. Remarkably, these distributions have the same temperature but different chemical potentials. This unusual thermodynamic state is causing a persistent nonequilibrium spin polarization only well above the Fermi energy. Femtosecond spin dynamics experiments performed on Fe_{3}O_{4} by time- and spin-resolved photoelectron spectroscopy support our model. Furthermore, the spin polarization response proves to be very robust and it can be adopted to selectively test the bulk HM character in a wide range of compounds.

Publisher's Note: Hydrogen Bonds in Excited State Proton Transfer [Phys. Rev. Lett. 117, 163002 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.117.163002.

Generation and Evolution of Spin-, Valley-, and Layer-Polarized Excited Carriers in Inversion-Symmetric WSe_{2}

We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe_{2}. Employing time- and angle-resolved photoelectron spectroscopy (trARPES) and complementary time-dependent density functional theory (TDDFT), we observe spin-, valley-, and layer-polarized excited state populations upon excitation with circularly polarized pump pulses, followed by ultrafast (<100  fs) scattering of carriers towards the global minimum of the conduction band. TDDFT reveals the character of the conduction band, into which electrons are initially excited, to be two-dimensional and localized within individual layers, whereas at the minimum of the conduction band, states have a three-dimensional character, facilitating interlayer charge transfer. These results establish the optical control of coupled spin-, valley-, and layer-polarized states in centrosymmetric materials with locally broken symmetries and suggest the suitability of TMDC multilayer and heterostructure materials for valleytronic and spintronic device concepts.

Hydrogen Bonds in Excited State Proton Transfer

Hydrogen bonding interactions between biological chromophores and their surrounding protein and solvent environment significantly affect the photochemical pathways of the chromophore and its biological function. A common first step in the dynamics of these systems is excited state proton transfer between the noncovalently bound molecules, which stabilizes the system against dissociation and principally alters relaxation pathways. Despite such fundamental importance, studying excited state proton transfer across a hydrogen bond has proven difficult, leaving uncertainties about the mechanism. Through time-resolved photoelectron imaging measurements, we demonstrate how the addition of a single hydrogen bond and the opening of an excited state proton transfer channel dramatically changes the outcome of a photochemical reaction, from rapid dissociation in the isolated chromophore to efficient stabilization and ground state recovery in the hydrogen bonded case, and uncover the mechanism of excited state proton transfer at a hydrogen bond, which follows sequential hydrogen and charge transfer processes.

Tracking Primary Thermalization Events in Graphene with Photoemission at Extreme Time Scales

Direct and inverse Auger scattering are amongst the primary processes that mediate the thermalization of hot carriers in semiconductors. These two processes involve the annihilation or generation of an electron-hole pair by exchanging energy with a third carrier, which is either accelerated or decelerated. Inverse Auger scattering is generally suppressed, as the decelerated carriers must have excess energies higher than the band gap itself. In graphene, which is gapless, inverse Auger scattering is, instead, predicted to be dominant at the earliest time delays. Here, <8  fs extreme-ultraviolet pulses are used to detect this imbalance, tracking both the number of excited electrons and their kinetic energy with time-and angle-resolved photoemission spectroscopy. Over a time window of approximately 25 fs after absorption of the pump pulse, we observe an increase in conduction band carrier density and a simultaneous decrease of the average carrier kinetic energy, revealing that relaxation is in fact dominated by inverse Auger scattering. Measurements of carrier scattering at extreme time scales by photoemission will serve as a guide to ultrafast control of electronic properties in solids for petahertz electronics.

Momentum-resolved spin dynamics of bulk and surface excited States in the topological insulator Bi(2)Se(3)

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 spin intensity signal over several orders of magnitude by spin-, time-, and angle-resolved photoemission spectroscopy can provide a comprehensive description of the optically excited electronic states in Bi_{2}Se_{3}. Our experiments reveal the existence of a surface resonance state in the second bulk band gap that is benchmarked by fully relativistic ab initio spin-resolved photoemission calculations. We propose that the newly reported state plays a major role in the ultrafast dynamics of the system, acting as a bottleneck for the interaction between the topologically protected surface state and the bulk conduction band. In fact, the spin-polarization dynamics in momentum space show that these states display macroscopically different temperatures and, more importantly, different cooling rates over several picoseconds.

A simple electron time-of-flight spectrometer for ultrafast vacuum ultraviolet photoelectron spectroscopy of liquid solutions

We present a simple electron time of flight spectrometer for time resolved photoelectron spectroscopy of liquid samples using a vacuum ultraviolet (VUV) source produced by high-harmonic generation. The field free spectrometer coupled with the time-preserving monochromator for the VUV at the Artemis facility of the Rutherford Appleton Laboratory achieves an energy resolution of 0.65 eV at 40 eV with a sub 100 fs temporal resolution. A key feature of the design is a differentially pumped drift tube allowing a microliquid jet to be aligned and started at ambient atmosphere while preserving a pressure of 10(-1) mbar at the micro channel plate detector. The pumping requirements for photoelectron (PE) spectroscopy in vacuum are presented, while the instrument performance is demonstrated with PE spectra of salt solutions in water. The capability of the instrument for time resolved measurements is demonstrated by observing the ultrafast (50 fs) vibrational excitation of water leading to temporary proton transfer.

POP-contaminated sites from HCH production in Sabiñánigo, Spain

In 2009, hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, and γ-HCH [lindane]) were listed as persistent organic pollutants (POP) in the Stockholm Convention. Accordingly, the legacy of HCH/lindane production with the associated large HCH waste deposits has become recognized as an issue of global concern and is addressed in the implementation of the Convention. The current paper gives an overview of the major contaminated sites from lindane production of the INQUINOSA Company. This company operated from 1975 to 1988 in the city of Sabiñánigo, Spain. HCH production resulted in the production of approximately 115,000 tonnes of waste isomers which were mainly dumped in two unlined landfills. These two landfill sites, together with the former production site, are recognized sources of environmental pollution. Assessment and remediation activities at these sites are described. A dense nonaqueous phase liquid (DNAPL) contaminated inter alia with HCH isomers, benzene, chlorobenzenes, and chlorophenols as the main contaminants and an associated contaminated groundwater plume have been discovered at both landfill/dumpsites and at the former production site. The approximately 4,000 t of DNAPLs constitute a serious risk for the environment due to the proximity of the Gállego River. Since 2004, more than 20 tonnes of this DNAPL has been extracted using "pump and treat" techniques. The Aragon Regional Government and the Spanish Environmental Ministry are taking action, focusing on the treatment of DNAPL and on the transfer of the large quantities of solid POP wastes to a new landfill. A range of laboratory tests has been performed in order to plan the aquifer remediation.

Clocking the melting transition of charge and lattice order in 1T-TaS2 with ultrafast extreme-ultraviolet angle-resolved photoemission spectroscopy

We use time- and angle-resolved photoemission spectroscopy with sub-30-fs extreme-ultraviolet pulses to map the time- and momentum-dependent electronic structure of photoexcited 1T-TaS(2). This compound is a two-dimensional Mott insulator with charge-density wave ordering. Charge order, evidenced by splitting between occupied subbands at the Brillouin zone boundary, melts well before the lattice responds. This challenges the view of a charge-density wave caused by electron-phonon coupling and Fermi-surface nesting alone, and suggests that electronic correlations play a key role in driving charge order.

Speciation of nickel by HPLC-UV/MS in pea nodules

A new and sensitive methodology based on normal phase HPLC has been developed for the speciation of nickel in low-complexity plant extracts. The method combines a silica stationary phase column, a 9:1 (v/v) hexane:ethanol mixture as mobile phase, and the detection of nickel complexes by either UV or MS. The developed methodology was applied to the speciation of nickel complexes in the cytoplasm of pea root nodules. Results obtained indicate that nickel citrate and nickel malate accounts for 99% of nickel present in pea nodule cytoplasm fraction. The low detection limit of the method (<0.2 nM) enables nickel speciation in non-hyperaccumulator plants.

Semi-covalent imprinted polymer using propazine methacrylate as template molecule for the clean-up of triazines in soil and vegetable samples

A semi-covalent imprinted polymer was prepared by precipitation polymerisation using propazine methacrylate as template molecule, ethylene glycol dimethacrylate as cross-linker and toluene as porogen. After removal of propazine by basic hydrolysis of the covalent bond, the optimum loading, washing and elution conditions for the solid-phase extraction of the selected triazines were established. The binding sites present in the polymeric matrix were characterised by fitting the experimental results of several rebinding studies to the Langmuir-Freundlich isotherm. Subsequently, an analytical methodology based on molecularly imprinted solid-phase extraction (MISPE) was developed for the determination of several triazinic herbicides in soil and vegetable samples. Following this procedure, a good degree of clean-up of the sample extracts was easily achieved, allowing the HPLC-UV determination of selected triazines in complex samples at low concentration levels.

Characterisation and quality assessment of binding sites on a propazine-imprinted polymer prepared by precipitation polymerisation

In this paper, the Langmuir-Freundlich isotherm (LF) is used to characterise a propazine-imprinted polymer obtained by precipitation polymerisation (MIP-P). Different rebinding studies were carried out allowing to explain the different interactions taking place between the molecularly imprinted polymer and six triazinic herbicides (desisopropylatrazine, desethylatrazine, simazine, atrazine, propazine and prometryn). The LF fitting parameters obtained (total number of binding sites, heterogeneity index and mean binding affinity) were compared to those obtained in a previous work for a propazine-imprinted polymer prepared by bulk polymerisation (MIP-B). From that study, it was concluded that precipitation polymerisation yielded polymers with a more homogeneous binding site distribution and higher affinity constants.

Clean-up of triazines in vegetable extracts by molecularly-imprinted solid-phase extraction using a propazine-imprinted polymer

An analytical methodology based on a molecularly imprinted solid-phase extraction (MISPE) procedure was developed for the determination of several triazines (atrazine, simazine, desethylatrazine (DEA), desisopropylatrazine (DIA), and propazine) in vegetable samples. A methacrylic acid-based imprinted polymer was prepared by precipitation polymerisation using propazine as template and toluene as porogen. After removal of the template by Soxhlet extraction, the optimum loading, washing, and elution conditions for MISPE of the selected triazines were established. The optimised MISPE procedure was applied to the extraction of the selected triazines in pea, potato, and corn sample extracts and a high degree of clean-up was obtained. However, some remaining interferences, non-specifically and strongly bound to the polymeric matrix, appeared in the chromatogram, preventing quantification of DIA in potatoes and DIA, DEA, and propazine in corn samples. Thus, a new clean-up protocol based on the use of a non-imprinted polymer for removal of these interferences prior to the MISPE step was developed. By following the new two-step MISPE procedure, the matrix compounds were almost completely removed, allowing the determination of all the triazines selected at concentration levels below the established maximum residue limits, making the developed procedure suitable for monitoring these analytes in vegetable samples.

Spin filtering of free electrons by magnetic multilayers: towards an efficient self-calibrated spin polarimeter

An asymmetrical ferromagnetic cobalt bilayer (18 nm Au/0.8 nm Co/2.2 nm Au/1.3 nm Co/1.5 nm Au) operates as a self-calibrated spin polarimeter with a high spin selectivity for free electrons injected at a few eV above the Fermi level. We present the analysis of transmitted currents as a function of the incident energy, based on a model of spin polarization dilution into the first gold layer and ballistic transport close to the vacuum level throughout the sample.