Research on Covid-19

At PSI, several projects are dedicated to important research questions concerning the Sars-CoV-2 coronavirus and the resulting diseases. We provide information on activities and projects, for example on investigations of lung tissue, on the production of proteins and antibodies or on ideas for new research on Covid-19.

Useful links

Effects of Quantum Spin-1/2 Impurities on the Magnetic Properties of Zigzag Spin Chains

We investigate the effect of Co2+ (spin-1/2) impurities on the magnetic ground state and low-lying spin excitations of the quasione-dimensional spin-1/2 antiferromagnet SrCuO2 by means of neutron scattering, muon spin spectroscopy, and bulk (ac and dc) magnetic susceptibilities. We found that dilute Co doping induces an Ising-like anisotropy and enhances the magnetic ordering temperature rather significantly, but preserves the gapless nature of the spin excitations.

Distinct Evolutions of Weyl Fermion Quasiparticles and Fermi Arcs with Bulk Band Topology in Weyl Semimetals

The Weyl semimetal phase is a recently discovered topological quantum state of matter characterized by the presence of topologically protected degeneracies near the Fermi level. These degeneracies are the source of exotic phenomena, including the realization of chiral Weyl fermions as quasiparticles in the bulk and the formation of Fermi arc states on the surfaces.

light switching.jpg

Light-switching of enzymatic activity on orthognonally functionalized polymer brushes

UV- and visible light-induced switching of enzymatic activity has been demonstrated using surface-grafted polymer brushes functionalized with microperoxidase MP-11 and spiropyran mojeties. Integration into an optofluidic device allowed reversible switching of the enzymatic activity under flow.

Room-temperature helimagnetism in FeGe thin films

Chiral magnets are promising materials for the realisation of high-density and low-power spintronic memory devices. For these future applications, a key requirement is the synthesis of appropriate materials in the form of thin films ordering well above room temperature. Driven by the Dzyaloshinskii-Moriya interaction, the cubic compound FeGe exhibits helimagnetism with a relatively high transition temperature of 278 K in bulk crystals.

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.

Silicon pixel barrel detector successfully installed in the CMS experiment

Middle of February the upgraded CMS silicon pixel barrel detector has been moved from PSI to CERN and was successfully installed in the CMS experiment.

Spiral spin-liquid and the emergence of a vortex-like state in MnSc2S4

Spirals and helices are common motifs of long-range order in magnetic solids, and they may also be organized into more complex emergent structures such as magnetic skyrmions and vortices. A new type of spiral state, the spiral spin-liquid, in which spins fluctuate collectively as spirals, has recently been predicted to exist.

1000 Structures solved at X06DA-PXIII

The macromolecular crystallography beamline X06DA-PXIII has reached 1,000 structures in the Protein Data Bank (PDB) on February 22, 2017.

Intermicellar Interactions and the Viscoelasticity of Surfactant Solutions: Complementary Use of SANS and SAXS

In ionic surfactant micelles, basic interactions among distinct parts of surfactant monomers, their counterion, and additives are fundamental to tuning molecular self-assembly and enhancing viscoelasticity. Here, we investigate the addition of sodium salicylate (NaSal) to hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB) and 1-hexadecylpyridinium chloride and bromide (CPyCl and CPyBr), which have distinct counterions and headgroup structures but the same hydrophobic tail.

SwissQuantum.png

Switzerland at the Quantum Crossroads document endorsed by QTC@PSI members

“Switzerland at the Quantum Crossroads” outlines the current quantum science and technology landscape in Switzerland, explains the promises of this technology and outlines the required steps for Switzerland to leverage its leadership in this space.

Oakton 2017 ACScat.jpg

IrO2‑TiO2: A High-Surface-Area, Active, and Stable Electrocatalyst for the Oxygen Evolution Reaction

We have developed a synthetic approach to highsurface-area chlorine-free iridium oxide nanoparticles dispersed in titania (IrO2-TiO2), which is a highly active and stable OER catalyst in acidic media. Operando X-ray absorption studies demonstrate the evolution of the surface species as a function of the applied potential, suggesting the conversion of the initial hydroxo surface layer to the oxo-terminated surface via anodic oxidation.

New magnetic phase in the nickelate perovskite TlNiO3

The RNiO3 perovskites are known to order antiferromagnetically below a material-dependent Néel temperature TN. We report experimental evidence indicating the existence of a second magnetically ordered phase in TlNiO3 above TN = 104K, obtained using nuclear magnetic resonance and muon spin rotation spectroscopy.

teaser image.png

PERFORM-60: Modelling the Ageing of Reactor Vessel Steels

The main threat to the reactor pressure vessel (RPV) operational safety is certainly the radiation damage that hardens and embrittles the steel it is made of. Four decades of research worldwide have allowed understanding and monitoring the phenomena that come into play. At the computational level, a simulation platform, PERFORM-60, has the ambitious aim of predicting the steel evolution for most RPV and operational conditions. It was initially elaborated in the frame of the EU project of the same acronym and is currently further developed to be the end-product of the on-going H2020 EU project SOTERIA. As a contribution of the Laboratory for Reactor Physics and Systems Behaviour (LRS) to SOTERIA, the platform has been rigorously assessed for the first time since its release on a real case study of a Swiss RPV. This critical assessment has been acknowledged by the community and serves as basis for improvements and future developments of the platform within SOTERIA.

GroupWengenSmall.jpg

Meeting on future directions with Mu3e in Wengen

We spent four days in Wengen, Switzerland, discussing ideas for physics with the Mu3e apparatus beyond the search for the lepton-flavour violating decay of the muon to three electrons. Collaboration members and theorists presented new ideas for future measurements with the high acceptance, high resolution Mu3e spectrometer using high intensity muon and pion beams at PSI. Technical challenges and promising R&D directions related to high-intensity data taking were also discussed in detail.

OutstandingPin.gif

Carlos Vaz Honored by the American Physical Society as Outstanding Referee 2017

SIM beamline scientist Carlos Vaz was recognized as outstanding referee for providing high quality peer review for the journals of the American Physical Society (APS).

Magnetic Field Dependence of Excitations Near Spin-Orbital Quantum Criticality

The spinel FeSc2S4 has been proposed to realize a near-critical spin-orbital singlet (SOS) state, where entangled spin and orbital moments fluctuate in a global singlet state on the verge of spin and orbital order.

Bild 1 Illimani.jpg

Deutschlandfunk: Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

Listen to an interview with Anja Eichler and Margit Schwikowski featuring new insights to the ancient copper metallurgy in the Andes as derived from ice-core archives.

Mu3e review at the PSI user meeting

In the context of the annual PSI user meeting, the Mu3e experiment underwent a detailed review by the research committee for particle physics at the ring cyclotron, discussing the preliminary version of the phase I Mu3e technical design report.

Probing current-induced magnetic fields in Au|YIG heterostructures with low-energy muon spin spectroscopy

We investigated the depth dependence of current-induced magnetic fields in a bilayer of a normal metal (Au) and a ferrimagnetic insulator (Yttrium Iron Garnet—YIG) by using low energy muon spin spectroscopy (LE-μSR). This allows us to explore how these fields vary from the Au surface down to the buried Au|YIG interface, which is relevant to study physics like the spin-Hall effect.

Nanocrystals formed on graphite.

In-situ Studies of the Reactivity of Model Catalysts: Surface Chemistry from flat surfaces to nanoparticles

On 7th February Dr. Christian Papp from University Erlangen (Germany) is visiting the SIM beamline and will give a Photon Science Seminar talk with the title: "In-situ Studies of the Reactivity of Model Catalysts: Surface Chemistry from flat surfaces to nanoparticles"

Thomas Lippert new Editor-in-Chief of Applied Physics A

Prof. Dr. Thomas Lippert has been appointed as new "Editor in Chief" of the journal Applied Physics A(link is external). He succeeds Michael Stuke who served Applied Physics A more than 20 years as an Editor in Chief.

Simulated strain distribution in a polymer reinforced Al cruciform sample subjected an equibiaxial load

A Miniaturized Biaxial Deformation Rig for in situ Mechanical Testing

Researchers at PSI have developed a new unique miniaturized biaxial deformation rig, which allows to apply in-plane biaxial stress states with arbitrary stress ratios and to perform strain path changes on thin-sheet metals. The device is optimized for in situ usage inside a scanning electron microscope and at synchrotron beam lines.