Lab News & Scientific Highlights
Highly Crystalline C8-BTBT Thin-Film Transistors by Lateral Homo-Epitaxial Growth on Printed Templates
Highly crystalline thin films of organic semiconductors offer great potential for high-performance, low-cost flexible electronics. Researchers at IMEC Belgium have developed a new double-step thin film fabrication process that offers higher performance devices. Soft X-ray spectro-microscopy at the Swiss Light Source was used to prove that the increased performance comes from larger areas of material sharing the same molecular orientation.
Atmosphere in X-ray light
PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
Composite laminated cruciform design for multiaxial testing of metals
Multiaxial mechanical testing of sheet metals is far from trivial, which is mainly related to issues with sample design and fabrication. PSI scientists have developed a new methodology to produce cruciform shaped samples from thin sheet metals based on a novel bottom-up approach. A proof-of-principle experiment based on polymer lamination of an aluminum thin sheet demonstrates the effectiveness of this new approach.
Dr. Nan Xu awarded SPS 2017 Prize in Condensed Matter Physics
The SPS 2017 Prize in Condensed Matter Physics, sponsored by IBM, has been awarded to Dr. Nan Xu for his excellent work on topological quantum states. Dr. Nan Xu is a joint postdoc of Paul Scherrer Institute (PSI) and the École Polytechnique Fédérale de Lausanne (EPFL).
A new RIXS analyzer scheme based on transmission zone plates
PSI scientists have developed a new type of X-ray optics that allows for analyzing the emission in resonant inelastic x-ray scattering (RIXS) experiments. The new approach combines the energy dispersion with imaging capabilities. In a collaborative effort with research groups from Göttingen and Hamburg, two new classes of RIXS experiments, energy mapping and RIXS imaging, have been demonstrated.
Single-shot Monitoring of Ultrafast Processes via X-ray Streaking at a Free Electron Laser
The advent of x-ray free electron lasers has extended the unique capabilities of resonant x-ray spectroscopy techniques to ultrafast time scales. Here, in collaboration between researchers from PSI, Sorbonne Universités, HASYLAB/DESY, Synchrotron SOLEIL, CNRS, and Uppsala University, we report on a novel experimental method that allows retrieving with a single x-ray pulse the time evolution of an ultrafast process, not only at a few discrete time delays, but continuously over an extended time window.
Stresses and Strains in cruciform samples deformed in tension
Cruciform experiments are very useful to study non-proportional strain path change behavior of engineering metals and alloys. This work studies the stress response of 6 prominently used cruciform geometries deformed under tension. Results show that for most of the cruciform samples, the gauge stresses are non-linearly coupled to the applied forces in both arms. Cruciform geometries based on the ISO standard are able to decouple these stresses but negligible gauge plastic strains are reached prior to failure.
Moving atoms with enhanced
THz pulses and tracking them with ultrashort x-ray pulses on an XFEL
Controlled motions of atoms using ultrashort electric field pulses allow to manipulated the properties of a material on ultrafast timescales. Here we show how metallic structures can be used to enhance a THz electric field pulse and track the induced atomic motions with ultrashort x-ray pulses emitted by a X-ray free electron laser.
Nonlinear electron-phonon coupling in doped manganites
We employ time-resolved resonant x-ray diffraction to study the insulator-to-metal transition that is launched via resonant excitation of an infrared-active optical phonon mode in a half doped manganite. We find that the charge order reduces promptly with a highly nonlinear (quartic) dependence on excitation fluence.