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This experiment performed at SwissFEL shows how fast we can localize electrons out of an electron gas into correlated, well localized states of a material. It is based on a combined ultrafast x-ray absorption and diffraction experiment on an intermetallic system.

Flows need sources and sinks. That’s why, in a new class of exotic materials called Weyl semimetals, the sources and sinks of Berry curvature – dubbed Weyl points – were believed to exist only in pairs. Now researchers at PSI have observed unpaired Weyl points for the first time in a crystalline solid. This discovery, which upends conventional thinking and the so-called Nielson-Niomiya no-go theorem, demonstrates the unique properties of "nodal wall" Weyl semimetals in comparison to conventional Weyl systems having only zero-dimensional Weyl nodes.

NZZ am Sonntag  has picked up this highlight in its issue on March 7th, 2021: The highlight refers to the analysis performed in SCCER Joint Activity Scenarios and Modelling, where PSI-LEA performed the analysis of the energy transition pathways.

An international team involving researchers from the University and University Hospital Zürich, the Krembil Research Institute and the University and University Hospital in Toronto (Canada), the Department of Physics of Jyväskylä (Finland), the University of Leuven (Belgium), the Johannes Kepler University in Linz (Austria), the Novartis Institutes for Biomedical Research in Emeryville (USA), the ETH Zürich and the Paul Scherrer Institute has developed a protocol that enables hierarchical imaging and computational analysis of vascular networks in entire postnatal- and adult mouse brains, enabling direct and quantitative comparisons of the morphological brain vascular network architecture between different postnatal and / or adult developmental stages. The results have been published on Nature Protocols on September 3rd, 2021.

Methane valorization is a promising technology to utilize this platform compound to produce aromatics and hydrocarbons. Researchers from PSI and ETH Zürich unveiled this reaction mechanism and observed the molecular growth from the ground up. Besides stepwise CH3 addition,  novel routes involving the dimerization of resonantly stabilized propargyl (C₃H₃) radicals to benzene (C₆H₆) were identified. These mechanistic insights will aid the development of valorisation strategies.

PSI is engaging in public outreach at a major event in Zürich, the "Scientifica" Science Days September 4 and 5.

Within this synergetic collaboration, PSI scientists have investigated the correlation between magnetic and electronic ordering in NdNiO3 by tuning its properties through proximity to a ferromagnetic manganite layer. The main outcome is that the stray magnetic field from the manganite layer causes a novel ferromagnetic-metallic (FM-M) phase in NNO. This work demonstrates the utilization of heterostructure engineering for creating novel quantum phases.

Perovskite oxynitride semiconductors have attracted huge interest recently as promising photoelectrode materials for photoelectrochemical (PEC) water splitting. Oxynitride thin films grown by physical vapor deposition are ideal model systems to study the fundamental physical and chemical properties of the surface of these materials, including their evolution. Using a combination of high-sensitivity low-energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS), the surface evolution of LaTiO_xN_y (LTON) and CaNbO_xN_y (CNON) thin films before and after the PEC characterizations is monitored. This work provides therefore insight into the surface characteristics and evolution of LTON and CNON oxynitride thin films as photoelectrodes for PEC applications.

Researchers from University of Zurich describe the experimental observation of a new orthorhombic structural phase in the superconducting iron-pnictide compound Pr₄Fe₂As₂Te_0.88O₄. In contrast to nematicity found in underdoped iron pnictides this phase transition is not electronically driven. 

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Employing X-ray magnetic circular dichroism (XMCD), angle-resolved photoemission spectroscopy (ARPES), and momentum-resolved density fluctuation (MRDF) theory, the magnetic and electronic properties of ultrathin NdNiO₃ (NNO) film in proximity to ferromagnetic (FM) La_0.67Sr_0.33MnO₃ (LSMO) layer are investigated. The experimental data shows the direct magnetic coupling between the nickelate film and the manganite layer which causes an unusual ferromagnetic (FM) phase in NNO. Moreover, it is shown the metal–insulator transition in the NNO layer, identified by an abrupt suppression of ARPES spectral weight near the Fermi level (E_F), is absent. This observation suggests that the insulating AFM ground state is quenched in proximity to the FM layer. Combining the experimental data (XMCD and AREPS) with the momentum-resolved density fluctuation calculation (MRDF) reveals a direct link between the MIT and the magnetic orders in NNO systems. This work demonstrates that the proximity layer order can be broadly used to modify physical properties and enrich the phase diagram of RENiO₃ (RE = rare-earth element).

The crystal structure and magnetic correlations in triangular antiferromagnet FeGa2S4 are studied by x-ray diffraction, magnetic susceptibility, neutron diffraction, and neutron inelastic scattering. We report significant mixing at the cation sites and disentangle magnetic properties dominated by major and minor magnetic sites.

A novel and noninvasive method for high-energy two-color x-ray FEL emission was demonstrated at SwissFEL. In the experiment, a laser emittance spoiler pulse is overlapped with the primary photocathode laser pulse to locally spoil the beam emittance and inhibit the FEL emission from the central part of the beam, ultimately resulting in X-ray emission at two wavelengths. High spectral stability and the possibility to independently control the duration and intensity ratio between the two-color X-ray pulses is demonstrated. The laser emittance spoiler also enables shot-to-shot selection between one and two-color FEL emission and further, as it does not contribute to beam losses, it is compatible with high repetition-rate FELs.

This article has been selected as the winner of the first Ernest Courant Outstanding Paper Recognition, a honor sponsored by the journal Physical Review Accelerators and Beams (PRAB) and the APS Division of Physics of Beams (DPB).  This honor recognizes the most outstanding paper published in PRAB annually.

GeTe that exhibits a strong anharmonicity and a ferroelectric phase transition between the rhombohedral and cubic structures has emerged as one of the leading thermoelectric materials. Herein, combining molecular dynamics simulations and inelastic neutron scattering measurements, the lattice dynamics in GeTe have been investigated to reveal the soft-mode mechanisms across the phase transition.

The introduction of tin into ceria strongly influences its reducibility. In turn, the reaction mechanism towards the oxidation of carbon monoxide changes: the oxidation rate increases, the apparent activation energy decreases and the reaction order in oxygen increases.

Cryo-full-field XANES computed tomography was used to visualize the presence and distribution of a second coordination polymer of reduced copper coordination within defect-engineered HKUST-1 MOF crystals. Observations encourage a revisitation of the structure-property relationships of defect-engineered MOFs.

The entire study is an investigation into the self-similarity behavior ^[1] of first and second order statistical quantities derived from a large-scale jet flow taken from one of the experiments in the PANDA facility using the Proper Orthogonal Decomposition (POD).

What is presented, are the merits, the potential and the characteristics of the corresponding underlying POD analysis. Proper Orthogonal Decomposition (POD) is a mathematical framework to extract large-scale structures which are otherwise eventually masked by the complexity of the fully turbulent flow; example: the meandering of a jet which is not so obvious for the original data.

Prof Philip Willmott, the author of the book 'Introduction to Synchrotron Radiation: techniques and applications' (second edition, John Wiley & Sons, Chichester, 2019. ISBN: 9781119280392), makes the scripts for the simulations and animations available to the public.

Pooja Thakkar received the Shoulders-Gray-Spindt award at the 34th Vacuum Nanoelectronics Conference for her paper "Voltage-controlled three-electron-beam interference by a three-element Boersch phase shifter with top and bottom shielding electrodes"

Imaging strain in crystalline materials with high resolution can be a challenging task. Researchers demonstrate an original use of X-ray ptychography for this purpose: ptychographic topography.

Magnetic anisotropy is anticipated to govern the formation of exotic spin textures reported recently in cubic chiral magnets, like low-temperature tilted conical and skyrmion lattice (SkL) states and metastable SkLs with various lattice geometry. Motivated by these findings, we quantified the cubic anisotropy in a series of CoZnMn-type cubic chiral magnets. We found that the strength of anisotropy is highly enhanced towards low temperatures. Moreover, not only the magnitude but also the character of cubic anisotropy drastically varies upon changing the Co/Mn ratio.

The rare earth nickelates RNiO₃ are metallic at high temperatures and insulating and magnetically ordered at low temperatures. The low temperature phase has been predicted to be type II multiferroic, i.e., ferroelectric and magnetic order are coupled and occur simultaneously. Confirmation of those ideas has been inhibited by the absence of experimental data on single crystals. Here we report on Raman spectroscopic data of RNiO₃ single crystals (R = Y, Er, Ho, Dy, Sm, Nd) for temperatures between 10 and 1000 K. Entering the magnetically ordered phase we observe the appearance of a large number of additional vibrational modes, implying a breaking of inversion symmetry expected for multiferroic order.

There is considerable evidence that the superconducting state of Sr₂RuO₄ breaks time reversal symmetry. In the experiments showing time reversal symmetry breaking, its onset temperature, T_TRSB, is generally found to match the critical temperature, T_c, within resolution. In combination with evidence for even parity, this result has led to consideration of a d_xz ± id_yz order parameter.

Fission products from the PSI-SINQ gas-jet facility, as operated by LRC, were used to reveal the separation of relevant radionuclides from radioactively contaminated water. The tests were conducted using a novel innovative filter material made of a blend of milk whey and active charcoal on cellulose. This material has been developed by the ETHZ spin-off BluAct Technologies GmbH.

The importance of this project was recently highlithed in ETSON/news

The electronic properties of transition-metal oxides with highly correlated electrons are of central importance in modern condensed-matter physics and chemistry, both for their fundamental scientific interest and for their potential for advanced electronic applications. However, the design of materials with tailored properties has been restricted by the limited understanding of their structure–property relationships, which are particularly complex in the proximity of the regime where localized electrons become gradually mobile. RENiO₃ perovskites, characterized by the presence of spontaneous metal to insulator transitions, are some of the most widely used model materials for the investigation of this region in theoretical studies. However, crucial experimental information needed to validate theoretical predictions is still lacking due to their challenging high-pressure synthesis, which has prevented to date the growth of sizable bulk single crystals with RE ≠ La, Pr, and Nd. Here we report the first successful growth of single crystals with RE = Nd, Sm, Gd, Dy, Y, Ho, Er, and Lu in sizes up to ∼75 μm, grown from molten salts in a temperature gradient under 2000 bar of oxygen gas pressure. The crystals display regular prismatic shapes with flat facets, and their crystal structures and metal–insulator and antiferromagnetic order transition temperatures are in excellent agreement with previously reported values obtained from polycrystalline samples. The availability of such crystals opens access to measurements that have hitherto been impossible to conduct. This should contribute to a better understanding of the fascinating properties of materials with highly correlated electrons and guide future efforts to engineer transition-metal oxides with tailored functional properties.

Schematic representation of the method used to grow RENiO₃ nickelate single crystals covering the full 4f series and Y. This novel procedure, based on the use of moderate oxygen gas pressures (2000 bar), solvothermal growth in a temperature gradient, and highly reactive eutectic salt mixtures as fluxes, yields prismatic-shaped crystals with flat facets and sizes up to ∼75 μm.

CeRh₂As₂, a nonsymmorphic heavy fermion material, was recently reported to host a remarkable temperature versus z-axis magnetic-field phase diagram with two superconducting phases. In this material, the two inequivalent Ce sites per unit cell, related by inversion symmetry, introduce a sublattice structure corresponding to an extra internal degree of freedom. In this work, we propose a classification of the possible superconducting states in CeRh₂As₂ from the two Ce-sites' perspective.

Intertwining quantum order and non-trivial topology is at the frontier of condensed matter physics. A charge- density-wave-like order with orbital currents has been pro- posed for achieving the quantum anomalous Hall effect in topological materials and for the hidden phase in cuprate high-temperature superconductors. However, the experimental realization of such an order is challenging. Here we use high-resolution scanning tunnelling microscopy to discover an unconventional chiral charge order in a kagome material, KV₃Sb₅, with both a topological band structure and a superconducting ground state.

The Kitaev quantum spin liquid epitomizes an entangled topological state, for which twoflavors of fractionalized low-energy excitations are predicted: the itinerant Majorana fermion and the Z₂ gauge flux. It was proposed recently that fingerprints of fractional excitations are encoded in the phonon spectra of Kitaev quantum spin liquids through a novel fractional- excitation-phonon coupling. Here, we detect anomalous phonon effects in α-RuCl₃ using inelastic X-ray scattering with meV resolution.

An article on the on-demand sample delivery and protein crystallography using acoustic levitation has been selected in an Applied Physics Letters collection of papers on technology and application of acoustic tweezers.

Encapsulation of highly dispersed palladium oxide clusters in the microporous channels and voids of the nanosized silicalite-1 crystals has been achieved by using an amine-based ligand.

The possibility of tuning the magnetic properties of materials with voltage (converse magnetoelectricity) or generating electric voltage with magnetic fields (direct magnetoelectricity) has opened new avenues in a large variety of technological fields, ranging from information technologies to healthcare devices and including a great number of multifunctional integrated systems, such as mechanical antennas, magnetometers, and radio frequency (RF) tunable inductors, which have been realized due to the strong strain-mediated magnetoelectric (ME) coupling found in ME composites. The development of single-phase multiferroic materials (which exhibit simultaneous ferroelectric and ferromagnetic or antiferromagnetic orders), multiferroic heterostructures, as well as progress in other ME mechanisms, such as electrostatic surface charging or magneto-ionics (voltage-driven ion migration), have a large potential to boost energy efficiency in spintronics and magnetic actuators. This article focuses on existing ME materials and devices and reviews the state of the art in their performance.

The silver ruthenium oxide AgRuO₃ consists of honeycomb Ru₂⁵⁺O₆²⁻ layers and can be considered and can be considered an analogue of SrRu₂O₆ with a different intercalation. We present measurements of magnetic susceptibility and specific heat on AgRuO₃ single crystals, which reveal a sharp antiferromagnetic transition at 342(3) K. The electrical transport in single crystals of AgRuO₃ is determined by a combination of activated conduction over an intrinsic semiconducting gap of ≈100 meV and carriers trapped and thermally released from defects.

In a study published in Nature Communications, researchers at the NHC Key Laboratory of Systems Biology of Pathogens in Beijing, China, in collaboration with the Paul Scherrer Institut characterize the interactions of SARS-CoV-2 orf9b and human TOM70 biochemically, and they determine the 2.2 Å crystal structure of the TOM70 cytosolic domain with a bound SARS-CoV-2 orf9b peptide.

Researchers from the University of Oxford, the Diamond Light Source and the Paul Scherrer Institut have generated strong evidence supporting one of two competing theories regarding the mechanism by which lithium metal dendrites grow through ceramic electrolytes. A process leading to short circuit at high rates of charge. The X-ray phase-contrast imaging capabilities of the TOMCAT beamline of the Swiss light source allowed researchers to visualize and characterize the growth of cracks and dendrites deep within an operating solid-state battery. The results were published in Nature Materials on April 22, 2021.

Various imaging methods in materials research have pursued the characterization of material composition and its change in space and time. When it comes to liquid matter far from equilibrium, such as mixing and evaporating mixtures of solutes and solvents, of paramount importance in diverse solution-processing methods, the quantitative and in situ characterization remains challenging. Our research with the evaporating ...

The step-wise oxidation of a new redox-active molecular semiconductor is recognized by changing shape, assembly behavior and other properties by spectro-microscopy correlation.