We report the main characteristics of the advanced photoelectric effect experiments beamline, operational at Elettra storage ring, featuring a fully independent double branch scheme obtained by the use of chicane undulators and able to keep polarization control in both linear and circular mode. The paper describes the novel technical solutions adopted, namely, (a) the design of a quasiperiodic undulator resulting in optimized suppression of higher harmonics over a large photon energy range (10–100 eV), (b) the thermal stability of optics under high heat load via cryocoolers, and (c) the end station interconnected setup allowing full access to off-beam and on-beam facilities and, at the same time, the integration of users’ specialized sample growth chambers or modules.

We have measured the resonant inelastic x-ray scattering (RIXS) spectra at the Cu $L_3$ edge in a variety of cuprates. Exploiting a considerably improved energy resolution (0.8 eV) we recorded significant dependencies on the sample composition and orientation, on the scattering geometry, and on the incident photon polarization. The RIXS final states correspond to two families of electronic excitations, having local ($dd$ excitations) and nonlocal (charge-transfer) character. The $dd$ energy splitting can be estimated with a simple crystal field model. The RIXS at the $L_3$ edge demonstrates here a great potential, thanks to the resonance strength and to the large $2p$ spin-orbit splitting.

A peculiar Rashba effect is found at a point in the Brillouin zone, where the time-reversal symmetry is broken, though this symmetry was believed to be a necessary condition for Rashba splitting. This finding obtained experimentally by photoemission measurements on a $\mathrm{Bi}/\mathrm{Si}(111)\mathrm{\text{−}}(\sqrt{3}\times \sqrt{3})$ surface is fully confirmed by a first-principles theoretical calculation. We found that the peculiar Rashba effect is simply understood by the two-dimensional symmetry of the surface, and that this effect leads to an unconventional nonvortical Rashba spin structure at a point with time-reversal invariance.

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 ${\mathrm{L}}_3$ PFY-XAS and RXES investigation of the intermediate valence compound ${\mathrm{YbAl}}_2$ 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 pressures explored until now, in order to cover the whole valence transition, which we find to be completed around 200 kbar. Moreover, the new data considerably reduce the experimental error bars on previous estimates and provide the most accurate description to date of this transition. We discuss the relative merits of various approaches to extract the $4f$ occupancy from the spectroscopic data.

The electronic and magnetic properties of cobalt-phthalocyanine (CoPc) molecules are modified at the interface with a magnetic metallic surface: upon adsorption of CoPc on iron film relevant changes are observed in the C 1s photoemission line shape and on Co L2,3 edges, and N K-edge x-ray absorption spectra. X-ray magnetic circular dichroism shows Co 3d spin-polarized states, i.e., magnetic coupling with the iron substrate at room temperature. The interplay among the electronic and magnetic properties and CoPc adsorption sites is fundamental for tailoring the functionalities of hybrid organic-metallic interfaces.

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.%):$\mathrm{Ce}$ at the $\mathrm{Ce}{\mathrm{L}}_3\left(2p\to 5d\right)$ and ${\mathrm{M}}_{4,5}\left(3d\to 4f\right)$ absorption edges. We deduce an increasing $4f$-band hybridization from the $\gamma$-phase stable at room temperature to the low-temperature $\alpha \text{−}\mathrm{Ce}$, consistent with the “Kondo collapse” scenario for the transition. The enhanced intrinsic resolution of $\mathrm{PFY}\text{−}\mathrm{XAS}$ allows us to resolve the elusive three-peak structure predicted by theory. Thanks to the selective enhancement typical of RXES, we could estimate the small but non-negligible contribution of the $f^2$ configuration in the hybrid ground state, and its change in the two phases. The linear dichroism effect in the ${\mathrm{M}}_{4,5}$ RXES spectra is consistent with the observed hybridization of $4f$ and conduction states.