Scientific Highlights
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.
X-ray nanotomography aids the production of eco-friendly solar cells
Polymer solar cells are in the spotlight for sustainable energy production of the future. Characterization of these devices by X-ray nanotomography helps to improve their production using environmentally friendly materials.
Strong enhancement of s-wave superconductivity near a quantum critical point of Ca3Ir4Sn13
We report microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca3Ir4Sn13 and Sr3Ir4Sn13 cubic compounds, which are members of the (Ca1−xSrx)3Ir4Sn13 system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW).
Controlling tunnelling in methane loss from acetone ions by deuteration
At the imaging Photoelectron Photoion Coincidence (iPEPICO) endstation of the VUV beamline evidence of H-atom tunneling was shown.
Direct evidence for a pressure-induced nodal superconducting gap in the Ba0.65Rb0.35Fe2As2 superconductor
The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. In contrast to other unconventional superconductors, in the Fe-HTSs both d-wave and extended s-wave pairing symmetries are close in energy. Probing the proximity between these very different superconducting states and identifying experi- mental parameters that can tune them is of central interest.
Intrinsic Paramagnetic Meissner Effect Due to s-Wave Odd-Frequency Superconductivity
In 1933, Meissner and Ochsenfeld reported the expulsion of magnetic flux - the diamagnetic Meissner effect - from the interior of superconducting lead. This discovery was crucial in formulating the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In exotic superconducting systems BCS theory does not strictly apply.
New EU project: Guiding light for the world's brightest light sources
EUCALL will build bridges between major laser and X-ray research centres: For the past half-century, two special kinds of light have changed the landscape of research. Advanced visible-spectrum optical lasers have propelled studies into ultrafast processes, new materials, telecommunications, and many other fields, while intense X-rays produced at synchrotrons have helped image tiny structures and otherwise invisible parts of matter, enabling huge leaps in biochemistry, pharmacology, and materials science. New developments have enhanced the generation of X-rays at optical-laser and accelerator facilities, resulting in the creation of large international research centres. The European Union is now funding a 7 million-euro effort to bring these research centres together through the European Cluster of Advanced Laser Light Sources (EUCALL) project.
Visualizing the morphology of vortex lattice domains in a bulk type-II superconductor
Alike materials in the solid state, the phase diagram of type-II superconductors exhibit crystalline, amorphous, liquid and spatially inhomogeneous phases. The multitude of different phases of vortex matter has thence proven to act as almost ideal model system for the study of both the underlying properties of superconductivity but also of general phenomena such as domain nucleation and morphology.
Visualizing the morphology of vortex lattice domains in a bulk type-II superconductor
Alike materials in the solid state, the phase diagram of type-II superconductors exhibit crystalline, amorphous, liquid and spatially inhomogeneous phases. The multitude of different phases of vortex matter has thence proven to act as almost ideal model system for the study of both the underlying properties of superconductivity but also of general phenomena such as domain nucleation and morphology.