Scientific Highlights
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.
Hard X-ray Photon Single-Shot Spectrometer of SwissFEL successfully delivered and installed
Not a joke: on 1st of April 2016 the Photon Single-Shot Spectrometer (PSSS) got delivered fully assembled and installed already to the front end of SwissFEL. It will measure the photon spectral information in every single shot for the Aramis beamline not only for the users, but also as a direct feedback to the machine during formation of the lasing process.
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.
Observation of Weyl nodes and Fermi arcs in tantalum phosphide
A Weyl semimetal possesses spin-polarized band-crossings, called Weyl nodes, connected by topological surface arcs. The low-energy excitations near the crossing points behave the same as massless Weyl fermions, leading to exotic properties like chiral anomaly. To have the transport properties dominated by Weyl fermions, Weyl nodes need to locate nearly at the chemical potential and enclosed by pairs of individual Fermi surfaces with non-zero Fermi Chern numbers.
Towards hybrid pixel detectors for energy-dispersive or soft X-ray photon science
JUNGFRAU (adJUstiNg Gain detector FoR the SwissFEL Aramis User station) is a two dimensional hybrid pixel detector for photon science applications at free electron lasers and synchrotron light sources. The JUNGFRAU 0.4 prototype presented here is specifically geared towards low-noise performance and hence soft X-ray detection. With an extremely low noise of less than 30 electrons it enters a field formally reserved for SSD’s and CMOS imagers allowing single photon resolution down to a photon energy of 500eV.
Semifluorinated Alkanes at the Air–Water Interface: Tailoring Structure and Rheology at the Molecular Scale
Semifluorinated alkanes form monolayers with interesting properties at the air–water interface due to their pronounced amphi-solvophobic nature and the stiffness of the fluorocarbons. In the present work, using a combination of structural and dynamic probes, we investigated how small molecular changes can be used to control the properties of such an interface, in particular its organization, rheology, and reversibility during compression–expansion cycles.
Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe2O6: NMR and Muon Spin Relaxation Studies
PbCuTe2O6 is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu2+ ions although additional interactions enhance the magnetic lattice connectivity.
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
Spin excitations in copper selenate, a skyrmion host material
Inelastic neutron scattering measurements performed at EIGER and TASP have mapped the magnetic excitation spectrum along high-symmetry directions of the first Brillouin zone for the magnetic skyrmion host copper selenate, Cu2OSeO3. Most of the observed spectrum is consistent with a recently proposed model for the magnetic excitations in Cu2OSeO3, for which a new set of best-fit dominant exchange parameters has been found.
Spin excitations in copper selenate, a skyrmion host material
G.S. Tucker et al., Physical Review B 93, 054401 (2016). Inelastic neutron scattering measurements performed at EIGER and TASP have mapped the magnetic excitation spectrum along high-symmetry directions of the first Brillouin zone for the magnetic skyrmion host copper selenate, Cu2OSeO3.