Atmosphere in X-ray light
PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
Dr. Nan Xu awarded SPS 2017 Prize in Condensed Matter Physics
The SPS 2017 Prize in Condensed Matter Physics, sponsored by IBM, has been awarded to Dr. Nan Xu for his excellent work on topological quantum states. Dr. Nan Xu is a joint postdoc of Paul Scherrer Institute (PSI) and the École Polytechnique Fédérale de Lausanne (EPFL).
Diving into magnets
For the first time, scientists have made visible the directions of the magnetisation inside a 3D magnetic object. The smallest details in their visualisation were ten thousand times smaller than a millimetre. Among others, the magnetic structure contained one outstanding kind of pattern: magnetic singularities called Bloch points, which up to now were only known in theory.
Nanomaterial helps store solar energy: efficiently and inexpensively
By combining a scalable cutting-edge synthesis method with time-resolved X-ray absorption spectroscopy measurements, it was possible to capture the dynamic local electronic and geometric structure during realistic operando conditions for highly active OER perovskite nanocatalysts.
Understanding the reaction mechanism in lignin catalytic fast pyrolysis
Lignin is a major constituent of plants, and may be used as a precursor for fuels and fine chemicals. Catalytic fast pyrolysis of lignin is one of the most promising approaches. By using vacuum ultraviolet synchrotron radiation and threshold photoelectron spectroscopy we could identify elusive intermediates, which are responsible for the formation of phenol and benzene and could thus tackle this reaction mechanism. Mechanistic understanding could enable targeted improvement of production methods in the future, beyond the currently used "cook-and-look" approach.
Photonic structure of white beetle wing scales: optimized by evolution
A very thin layer on this beetle’s wings exhibits a complicated structure on the nanoscale that gives them a bright white color. X-ray nanotomography acquired at the Swiss Light Source provides a faithful image of this structure in three dimensions with which scientists can confirm its evolutionary optimization: just enough material for an efficient reflection of white light.
Isomer-Selective Generation and Spectroscopic Characterization of Biofuel Intermediates
Online combustion analysis relies heavily on spectral data to detect reactive intermediates isomer-selectively to establish e.g. kinetic flame models. Due to the difficulty to generate these species cleanly, spectral data are rather scarce. Here we report on the selective generation of three picolyl radical isomers (C5H4N-CH2*) by deamination of aminomethylpyridines. Picolyl radicals are relevant in biofuel combustion, and could now be characterized by threshold photoelectron spectroscopy using synchrotron radiation. Vibrationally resolved bands and distinct ionization energies allow for isomer-specific detection of these elusive species in complex environments and permit us to explore new avenues in soot- and NOx formation kinetics.
Towards understanding of human betacoronavirus HKU1 life cycle
Researchers from China and USA join forces with Swiss Light Source (SLS) macromolecular crystallography (MX) beamline scientists in a study, which aims at understanding an important step in the life cycle of the human betacoronavirus HKU1.
3-D X-ray imaging makes the finest details of a computer chip visible
Researchers at the PSI have made detailed 3-D X-ray images of a commercially available computer chip. In their experiment, they examined a small piece that they had cut out of the chip beforehand. This sample remained undamaged throughout the measurement. It is a major challenge for manufacturers to determine if, in the end, the structure of their chips conforms to the specifications. Thus these results represent one important application of an X-ray tomography method that the PSI researchers have been developing for several years.
Interlaced zone plates push the resolution limit in x-ray microscopy
A novel type of diffractive lenses based on interlaced structures enable x-ray imaging at resolutions below 10 nm. The fabrication method and the test results of these novel x-ray lenses have been published in the journal Scientific Reports.
Nanotechnology enables new insights into chemical reactions
Eighty percent of all products of the chemical industry are manufactured with catalytic processes. Catalysis is also indispensable in energy conversion and treatment of exhaust gases. Industry is always testing new substances and arrangements that could lead to new and better catalytic processes. Researchers of the Paul Scherrer Institute PSI in Villigen and ETH Zurich have now developed a method for improving the precision of such experiments, which may speed up the search for optimal solutions.
The Smallest Magnet
Single holmium atoms adsorbed on few monolayers of magnesium oxide are extraordinarily stable magnets. They retain a significant fraction of their magnetization when the external magnetic field is switched off. This has been shown recently in a study combining x-ray magnetic circular dichroism performed at the Swiss Light Source (SLS) and at the European Synchrotron Radiation Facility (ESRF) as well as scanning tunneling microscopy. The results open perspectives of storing and processing information at ultrahigh density.
Novel insulating phase in iron-pnictide materials
The first example of an insulating phase which is close to the superconducting phase in an iron-pnictide system has been recently observed in heavy Cu-doped NaFe1-xCuxAs (x > 0.3). A combined study by angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations revealed that on-site Coulomb repulsion and enhanced Hund’s rule coupling are responsible for the insulating behavior. The results show that the insulating phase in NaFe0.5Cu0.5As resembles the situation in the parent compounds of the high-Tc cuprate superconductors.
Selectively conductive or insulating
The material neodymium nickel oxide is either a metal or an insulator, depending on its temperature. The possibility to control this transition electrically makes the material a potential candidate for transistors in modern electronic devices. By means of a sophisticated development of X-ray scattering, researchers at the Paul Scherrer Institute PSI have now been able to track down the cause of this transition: electrons around the oxygen atoms are rearranging.
Magnesium Oxide Boosts the Hysteresis of Single-Molecule Magnets
Researchers from PSI and EPFL have demonstrated that the magnetization hysteresis and remanence of TbPc2 single-molecule magnets drastically depends on the substrate on which they are deposited. If a few atomic layers thick magnesium oxide film grown on a silver substrate is used, a record wide hysteresis and record large remanence can be obtained. Single-molecule magnets are attractive for molecular spintronics applications such as information processing or storage.
Shedding light on the origins of high-Tc superconductivity in bismuth oxides
Researchers have overcome a number of challenges in order to employ an advanced probe in the study of an unusual material, barium bismuth oxide (BaBiO3) – an insulating parent compound of a family of high-temperature superconductors known since the late 80s. In order to finally realize the experiments, the researchers grew and studied thin films of the material completely in situ under ultrahigh vacuum conditions. The results show that superconductivity in bismuth oxides emerges out of a novel insulating phase, where hole pairs located on combinations of the oxygen orbitals are coupled with distortions of the crystal lattice.
Single shot grating interferometry demonstrated using direct conversion detection
Researchers at the Paul Scherrer Institute's Swiss Light Source in Villigen, Switzerland, have developed an X-ray grating interferometry setup which does not require an analyzer grating, by directly detecting the fringes generated by the phase grating with a high resolution detector. The 25um pitch GOTTHARD microstrip detector utilizes a direct conversion sensor in which the charge generated from a single absorbed photon is collected by more than one channel. Therefore it is possible to interpolate to achieve a position resolution finer than the strip pitch.
How does food look like on the nanoscale?
The answer to this question could save food industry a lot of money and reduce food waste caused by faulty production. Researchers from the University of Copenhagen and the Paul Scherrer Institut have obtained a 3D image of food on the nanoscale using ptychographic X-ray computed tomography. This work paves the way towards a more detailed knowledge of the structure of complex food systems.
Tailoring Novel Superconductivity
The Angle Resolved Photoemission Spectroscopy (ARPES) measurements performed on 2DEL at STO surface revealed that, at low carrier density, electrons are always accompanied by a quantized dynamic lattice deformation. Together with the electron, these phonon-cloud formed a new composite quasiparticle called Fröhlich polaron.
Researchers find key to zinc rich plants to combat malnutrition
The diet in many developing countries is lacking zinc, but researchers have just solved the riddle of how to get more zinc into crop seeds. The discovery has been published in Nature Plants, and the research was led by University of Copenhagen.By Johanne Uhrenholt Kusnitzoff
Watching lithium move in battery materials
In order to understand limitations in current battery materials and systematically engineer better ones, it is helpful to be able to directly visualize the lithium dynamics in materials during battery charge and discharge. Researchers at ETH Zurich and Paul Scherrer Institute have demonstrated a way to do this.
New particle could form the basis of energy-saving electronics
The Weyl fermion, just discovered in the past year, moves through materials practically without resistance. Now researchers are showing how it could be put to use in electronic components.
High-performance thermoelectric nanocomposites from nanocrystal building blocks
Using an assembly of colloidal nanocrystals a Ag-PbS nanocomposite was produced with increased thermoelectic figures of merit up to 1.7K at 850 K. EXAFS spectroscopy at the Ag K-edge was essential to show that Ag does not dissolve in PbS nanoparticles but preserved the individual nanodomains. This reduces the PbS intergrain energy barriers for charge transport
Slowed down current could point the way to energy-saving computers
Computers and other electronic devices account for a substantial portion of worldwide energy use. With today’s technologies, it is not possible to reduce this energy consumption significantly any further; chips in the energy-saving electronics of the future will hence have to be made from novel materials. Researchers at the Paul Scherrer Institute PSI have now found important clues in the search for such materials.
Mass density distribution of intact cell ultrastructure
The determination of the mass density of cellular compartments is one of the many analytical tools that biologists need to unravel the extremely complex structure of biological systems. Cryo X-ray nanotomography reveals absolute mass density maps of frozen hydrated cells in three dimensions.
Preserved Embryos Illustrate Seed Dormancy in Early Angiosperms
The discovery of exceptionally well-preserved, tiny fossil seeds dating back to the Early Cretaceous corroborates that flowering plants were small opportunistic colonizers at that time, according to a new Yale-led study.
First EIGER X 16M in operation at the Swiss Light Source
The macromolecular crystallography beamline X06SA at the Swiss Light Source, a synchrotron operated by Paul Scherrer Institute, is the first one in the world to upgrade its detector to an EIGER X 16M.
3D nanostructure of a bone made visible
Bones are made up of tiny fibres that are roughly a thousand times finer than a human hair. Researchers at the Paul Scherrer Institute PSI have developed a new computer-based algorithm with which they were able to visualize the localised order and alignment of these nanostructures inside an entire piece of bone for the first time.
Observation of Fermi-Arc Spin Texture in TaAs
The study of nontrivial topological semimetals (TSM) is an emerging subject, providing a new frontier in topological aspects beyond insulators. Here, we have investigated the spin texture of surface Fermi arcs in the recently discovered Weyl semimetal TaAs using spin- and angle-resolved photoemission spectroscopy. The experimental results demonstrate that the Fermi arcs are spin polarized. The measured spin texture fulfills the requirement of mirror and time-reversal symmetries and is well reproduced by our first-principles calculations, which gives strong evidence for the topologically nontrivial Weyl semimetal state in TaAs. The consistency between the experimental and calculated results further confirms the distribution of chirality of the Weyl nodes determined by first principles calculations.
Excited states at interfaces of a metal-supported ultrathin oxide film
At the PEARL beamline, metal-supported ultrathin oxide films have been studied which are a class of materials of technological importance in various research fields such as catalysis, spintronics, or nanoelectronics.