Scientific Highlights
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 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.
Cover page of CHEMCATCHEM
A paper titled "Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol" by Zhiqiang Ma is published in ChemCatChem and made it on the cover of issue 6/2017.
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.
Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago
Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Based on a 6500 year ice-core Cu record from Illimani glacier in Bolivia we provide the first complete history of large-scale Cu smelting activities in South America. Earliest anthropogenic Cu pollution was found during the Early Horizon period ~700-50 BC. We attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.
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.