Scientific Highlights
Weyl spin-momentum locking in a chiral topological semimetal
Spin–orbit coupling in noncentrosymmetric crystals leads to spin–momentum locking – a directional relationship between an electron’s spin angular momentum and its linear momentum. Isotropic orthogonal Rashba spin–momentum locking has been studied for decades, while its counterpart, isotropic parallel Weyl spin–momentum locking has remained elusive in experiments. Theory predicts ...
Alavi-Mandell Award 2024 from the Journal of Nuclear Medicine (JNM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI)
We congratulate Dr. Chiara Favaretto for the excellent research work she did during her time at the Center for Radiopharmaceutical Sciences.
Surface oxidation/spin state determines oxygen evolution reaction activity of cobalt-based catalysts in acidic environment
Co-based catalysts are promising candidates to replace Ir/Ru-based oxides for oxygen evolution reaction (OER) catalysis in an acidic environment. However, both the reaction mechanism and the active species under acidic conditions remain unclear. In this study, by combining surface-sensitive soft X-ray absorption spectroscopy characterization with electrochemical analysis, we discover that the acidic OER activity of Co-based catalysts are determined by their surface oxidation/spin state.
All Two-Loop Feynman Integrals for Five-Point One-Mass Scattering
We compute the complete set of two-loop master integrals for the scattering of four massless particles and a massive one. Our results are ready for phenomenological applications, removing a major obstacle to the computation of complete next-to-next-to-leading order QCD corrections to processes such as the production of a H/Z/W boson in association with two jets at the LHC. Furthermore ...
High-resolution ptychographic imaging at a seeded free-electron laser source using OAM beams
Electromagnetic waves possessing orbital angular momentum (OAM) are powerful tools for applications in optical communications, quantum technologies, and optical tweezers. Now, a consortium of collaborators in France, Italy, Slovenia, Spain, Switzerland, Sweden, and the US reports on using such beams in the extreme ultraviolet region for ptychographic imaging in the cover page article of Optica 11, Issue 3. By controlling the topological charge, the researchers achieve an improvement of 30% in image resolution.
What will the SLS 2.0 upgrade mean for experiments?
Tighter beams, brighter light and extended photon energies open new experimental possibilities.
Electron Glass Phase with Resilient Zhang-Rice Singlets in LiCu3O3
LiCu3O3 is an antiferromagnetic mixed valence cuprate where trilayers of edge-sharing Cu(II)O (3d9) are sandwiched in between planes of Cu(I) (3d10) ions, with Li stochastically substituting Cu(II). Angle-resolved photoemission spectroscopy (ARPES) and density functional theory reveal two insulating electronic subsystems that are segregated in spite of sharing common oxygen atoms: a Cu dz2/O pz derived valence band (VB) dispersing on the Cu(I) plane, and a Cu 3dx2−y2/O 2px,y derived Zhang-Rice singlet (ZRS) band dispersing on the Cu(II)O planes.
Developing detectors to transform science with light (part 2)
Part II: Why detecting soft X-rays is hard, and how a new breakthrough is set to transform low energy X-ray science.
Flat-band hybridization between f and d states near the Fermi energy of SmCoIn5
We present high-quality angle-resolved photoemission (ARPES) and density functional theory calculations (DFT+U) of SmCoIn5. We find broad agreement with previously published studies of LaCoIn5 and CeCoIn5, confirming that the Sm 4f electrons are mostly localized. Nevertheless, our model is consistent with an additional delocalized Sm component, stemming from hybridization between the 4f electrons and the metallic bands at “hot spot” positions in the Brillouin zone.
Efficient transient X-ray absorption spectroscopy
By combining the unique large bandwidth emission mode of SwissFEL’s ARAMIS undulator and diffractive X-ray optics made of diamond, we have demonstrated a new method for time-resolved X-ray absorption near edge structure (XANES) spectroscopy that enables faster data acquisition and requires smaller sample quantities for high-quality data.