Shifting away from nuclear energy, expanding solar and wind power, generating energy from biomass, reducing energy consumption. Switzerland is committed to becoming climate-neutral by 2050. An ambitious goal, which has become more urgent than ever due to the increasingly challenging geopolitical situation. How can a sustainable and resilient energy supply for Switzerland be established over the coming years? What's the optimal way to use renewable energy sources? What new technologies are especially promising? At PSI, researchers are seeking answers to these crucial questions.
New Renewables on integration course
The Swiss government’s Energy Strategy 2050 includes a significant expansion of renewable energy such as solar and wind power. The integration of this electric energy, which is produced in a decentralised way and with temporal fluctuations, poses a major challenge for power grids. One possible solution involves using the electricity surplus that would otherwise overload the grid for the production of gases such as hydrogen or methane. The electric energy would thus be stored temporarily in form of chemical energy. These gaseous energy carriers can be converted back into electricity, heat or kinetic energy (in gas engines) at a later date as and when needed. Dubbed power to gas, the concept is the focus of the new Energy System Integration (ESI) Platform at PSI.
Foundation Stone Ceremony Marks Scientific Importance of ESS
Today, several hundred members of the European scientific community gathered at the European Spallation Source (ESS) construction site in Lund, Sweden, for the ESS Foundation Stone Ceremony. The event was held to lay the foundation’ both for the new facility, which has recently begun construction, and for a new generation of science in Europe.
The last piece of the puzzle
Julia H. Smith is a postdoctoral fellow working on detectors for the SwissFEL x-ray free electron laser, which can be envisioned as the eyes of the new PSI large research facility. During her time at PSI, she has a good chance of accompanying her detector up to its use at the new facility. Even more important than witnessing the first experiments at SwissFEL is acquiring new knowledge and skills during my time as a postdoc at PSI. Smith would like to continue working in the field of detectors and technology development after her postdoc – at a company or at another research institute.
Direct Spectroscopic Observation of a Shallow Hydrogenlike Donor State in Insulating SrTiO3
We present a direct spectroscopic observation of a shallow hydrogenlike muonium state in SrTiO3 which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below ∼70 K. From the temperature dependence we estimate an activation energy of ∼50 meV in the bulk and ∼23 meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor.
The μ → eγ decay in a systematic effective field
We implement a systematic effective field theory approach to the benchmark process μ → eγ, performing automated one-loop computations including dimension 6 operators and studying their anomalous dimensions. We obtain limits on Wilson coefficients of a relevant subset of lepton-flavour violating operators that contribute to the branching ratio μ → eγ at one-loop.
Giants who control miniscule particles
Magnets are the unsung heroes in particle accelerators because they keep protons or electrons on track. But such magnets have very little in common with the small ones on the domestic fridge door. Quite a few of the magnets at PSI are heavier and bulkier than the fridge itself, yet despite this they are also masterpieces of precision and control.
A reliable type from the 1980s
The source of the proton beam at PSI is a retro-style Cockcroft-Walton linear accelerator. Since 1984 it has been the first acceleration stage for protons which are taken up to around 80 percent of the speed of light by two further ring accelerators. This has resulted in the generation of a significant proton beam over decades, and which has even held the world record as the highest performing beam since 1994 thanks to ongoing retrofitting.
Airpocalypse explained
The causes of China's record level fine particulate pollution in winter 2013 At the beginning of 2013 a greyish-brown blanket of smog lay over large areas of China for several months. The fine particle pollution was higher by 1 to 2 orders of magnitude than the levels normally measured in Western Europe and the United States. An international team of researchers under the lead of the Paul Scherrer Institute PSI and the Institute of Earth Environment, Chinese Academy of the Sciences revealed the causes of the airpocalypse. The study published in the journal Nature also describes what steps are to be taken to prevent an environmental crisis of this kind in the future.
Energiewende in Reinkultur – in Wädenswil zu bestaunen
Der am Paul Scherrer Institut PSI entwickelte Prozess der hydrothermalen Methanierung von wässriger Biomasse erreicht einen wichtigen Meilenstein: Dank der Zusammenarbeit im neuen Kompetenzzentrum des Bundes für Bioenergie BIOSWEET konnten Forschende des PSI, der ZHAW, der ETH Lausanne, der Empa und der Hochschule für Technik Rapperswil die technische Machbarkeit der Methanherstellung aus Mikroalgen demonstrieren. Der dazu verwendete Algenbioreaktor sowie die Anlage zur Methanierung der Algen können am 24. September auf dem Campus Grüental der ZHAW in Wädenswil besichtigt werden. Für Medienschaffende gibt es von 14:00 bis 14:30 eine spezielle Führung.This news release is only available in German.
Electric-Field-Induced Skyrmion Distortion and Giant Lattice Rotation in the Magnetoelectric Insulator Cu2OSeO3
Discovering fundamentally new ways to manipulate magnetic spins is crucial for research into advanced technologies. Magnetic Skyrmions, which are topologically stable whirls of magnetic spins, are promising candidates for new device components since those found in metallic host materials can be manipulated using electric currents.
New material generated with light
PSI researchers garner experience for SwissFEL experimentsAided by short laser flashes, researchers at the Paul Scherrer Institute have managed to temporarily change a material’s properties to such a degree that they have à to a certain extent àcreated a new material. This was done using the x-ray laser LCLS in California. Once the PSI x-ray laser SwissFEL is up and running, experiments of this kind will also be possible at PSI.
Controlling the near-surface superfluid density in under doped YBa2Cu3O6+x by photo-illumination
The interaction with light weakens the superconducting ground state in classical superconductors. The situation in cuprate superconductors is more complicated: illumination increases the charge carrier density, a photo-induced effect that persists below room temperature. Furthermore, systematic investigations in underdoped YBa2Cu3O6+x (YBCO) have shown an enhanced critical temperature Tc. Until now, studies of photo-persistent conductivity (PPC) have been limited to investigations of structural and transport properties, as well as the onset of superconductivity.
Plasma interactions determine the composition in pulsed laser deposited thin films
Plasma chemistry and scattering strongly affect the congruent, elemental transfer during pulsed laser deposition of target metal species in an oxygen atmosphere. Studying the plasma properties of La0.6Sr0.4MnO3, we demonstrate for as grown La0.6Sr0.4MnO3-δ films that a congruent transfer of metallic species is achieved in two pressure windows: ∼10−3 mbar and ∼2 × 10−1 mbar.
Low-temperature solid-oxide fuel cells based on proton-conducting electrolytes
The need for reducing the operating temperature of solid-oxide fuel cells (SOFCs) imposed by cost reduction has pushed significant progress in fundamental understanding of the individual components, as well as materials innovation and device engineering. Proton-conducting oxides have emerged as potential alternative electrolyte materials to oxygen-ion conducting oxides for operation at low and intermediate temperatures.
Mixed Dimensionality of Confined Conducting Electrons in the Surface Region of SrTiO3
Using angle-resolved photoemission spectroscopy, we show that the recently discovered surface state on SrTiO3 consists of nondegenerate t2g states with different dimensional characters.
Jurassic Welsh mammals were picky eaters, study finds
New analyses of tiny fossil mammals from South Wales are shedding light on the function and diets of our earliest ancestors, a team led by researchers from the Universities of Bristol and Leicester report in the journal Nature. The team used CT scanning with synchrotron X-rays at PSI’s Swiss Light Source to reveal in unprecedented detail the internal anatomy of the mammals’ tiny jaws.
A revealing mixture: The surface of an oxide insulator can host two distinct types of conducting electrons
Strontium titanate, SrTiO3, is an important material for the realization of next-generation electronic devices. A famous example is the interface of LaAlO3 grown on SrTiO3, which is metallic and magnetic at its interface, even though the individual compounds are insulating and nonmagnetic in bulk form. The physics behind how novel interface states form on SrTiO3 - and how they become endowed with such surprising properties - is not well understood.
Spin-lattice coupling induced weak dynamical magnetism in EuTiO3 at high temperatures
EuTiO3, which is a G-type antiferromagnet below TN = 5.5 K, has some fascinating properties at high temperatures, suggesting that macroscopically hidden dynamically fluctuating weak magnetism exists at high temperatures. This conjecture is substantiated by magnetic field dependent magnetization measurements, which exhibit pronounced anomalies below 200 K becoming more distinctive with increasing magnetic field strength. Additional results from muon spin rotation experiments provide evidence for weak fluctuating bulk magnetism induced by spin-lattice coupling which is strongly supported in increasing magnetic field.
Low-Temperature Micro-Solid Oxide Fuel Cells with Partially Amorphous La0.6Sr0.4CoO3-δ Cathodes
Partially amorphous La0.6Sr0.4CoO3-δ (LSC) thin-film cathodes are fabricated using pulsed laser deposition and are integrated in free-standing micro-solid oxide fuel cells (micro-SOFC) with a 3YSZ electrolyte and a Pt anode. A low degree of crystallinity of the LSC layers is achieved by taking advantage of the miniaturization of the cells, which permits low-temperature operation (300–450 °C).
What attacks on oil pipelines have in common with epidemics
How susceptible is the global energy infrastructure to attacks by non-state actors? Has the number of attacks on this infrastructure actually increased of late? Which regions of the world are especially vulnerable? And which tactics do the attackers use? Scientists are looking to find the answers to these and other related questions with the aid of a database developed by researchers from the Center of Security Studies at ETH Zurich in collaboration with the Paul Scherrer Institute PSI.
Correlated Decay of Triplet Excitations in the Shastry-Sutherland Compound SrCu2(BO3)2
The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu2(BO3)2 is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature, while the integrated spectral weight can be explained by an isolated dimer model up to 10 K.
Fast scanning coherent X-ray imaging using Eiger
The smaller pixel size, high frame rate, and high dynamic range of next-generation photon counting pixel detectors expedites measurements based on coherent diffractive imaging (CDI). The latter comprises methods that exploit the coherence of X-ray synchrotron sources to replace imaging optics by reconstruction algorithms. Researchers from the Paul Scherrer Institut have recently demonstrated fast CDI image acquisition above 25,000 resolution elements per second using an in-house developed Eiger detector. This rate is state of the art for diffractive imaging and even on a par with the fastest scanning X-ray transmission instruments. High image throughput is of crucial importance for both materials and biological sciences for studies with representative population sampling.
Square dance of the atoms: Shedding light on ultrafast phase transitions
The exploration of the interaction of structural and electronic degrees of freedom in strongly correlated electron systems on the femtosecond time scale is an emerging area of research. One goal of these studies is to advance our understanding of the underlying correlations, another to find ways to control the exciting properties of these materials on an ultrafast time scale.
Square dance of the atoms: Shedding light on ultrafast phase transitions
The exploration of the interaction of structural and electronic degrees of freedom in strongly correlated electron systems on the femtosecond time scale is an emerging area of research. One goal of these studies is to advance our understanding of the underlying correlations, another to find ways to control the exciting properties of these materials on an ultrafast time scale. So far a general model is lacking that provides a quantitiative description of the correlations between the structural and electronic degrees of freedom.
Negative Oxygen Isotope Effect on the Static Spin Stripe Order in Superconducting La2−xBaxCuO4(x=1/8) Observed by Muon-Spin Rot
Large negative oxygen-isotope (16O and 18O) effects (OIEs) on the static spin-stripe-ordering temperature Tso and the magnetic volume fraction Vm were observed in La2−xBaxCuO4(x=1/8) by means of muon-spin-rotation experiments. The corresponding OIE exponents were found to be αTso=-0.57(6) and αVm=-0.71(9), which are sign reversed to αTC=0.46(6) measured for the superconducting transition temperature Tc. This indicates that the electron-lattice interaction is involved in the stripe formation and plays an important role in the competition between bulk superconductivity and static stripe order in the cuprates.
Direct observation of the spin texture in SmB6 as evidence of the topological Kondo insulator
Topological Kondo insulators have been proposed as a new class of topological insulators in which non-trivial surface states reside in the bulk Kondo band gap at low temperature due to strong spin–orbit coupling. In contrast to other three-dimensional topological insulators, a topological Kondo insulator is truly bulk insulating. Furthermore, strong electron correlations are present in the system, which may interact with the novel topological phase. By applying spin- and angle-resolved photoemission spectroscopy, here we show that the surface states of SmB6 are spin polarized. The spin is locked to the crystal momentum, fulfilling time reversal and crystal symmetries.
Insulator makes electrons move in an ordered way
Researchers at the PSI, the EPFL and the Chinese Academy of Science, have proven that the material SmB6 shows all the properties of a so called topological insulator à a material with electric currents flowing along its surface with all of them being polarized. Here, the property is very robust, i.e. the only current that can flow is spin polarized and is not easily destroyed by small irregularities in the structure or composition of the material. Spin polarized currents are necessary for spintronics, electronics using the electrons’ spin.
Small-angle neutron scattering study of the mixed state of Yb3Rh4Sn13
Using the small angle neutron scattering (SANS) technique we investigated the vortex lattice (VL) in the mixed state of the stannide superconductor Yb3Rh4Sn13. We find a single domain VL of slightly distorted hexagonal geometry for field strengths between 350 and 18 500 G and temperatures between T=0.05 and 6.5 K. We observe a clear in-plane rotation of the VL for different magnetic field directions relative to the crystallographic axes.
Spin-Wave Spectrum of the Quantum Ferromagnet on the Pyrochlore Lattice Lu2V2O7
Neutron inelastic scattering has been used to probe the spin dynamics of the quantum (S=1/2) ferromagnet on the pyrochlore lattice Lu2V2O7. Well-defined spin waves are observed at all energies and wave vectors, allowing us to determine the parameters of the Hamiltonian of the system.
Hydrogen: a Trojan horse in fuel-rod cladding tubes
In nuclear reactors, water is dissociated at the surface of the hot fuel elements, thereby producing hydrogen. This hydrogen can penetrate the fuel cladding surrounding the actual fuel and weaken it mechanically. Researchers from the Paul Scherrer Institute (PSI) have been using neutrons and synchrotron radiation to study how the hydrogen gets into the cladding tube and what impact it can have once inside.