Lab News & Scientific Highlights
An iodine polymeric chain with tunable conductivity
The progressive hydrostatic compression of I2 and I3- units in an organic salt lead to a homoatomic polymeric chain. As the I---I distance collapses the covalent character of the interaction becomes more relevant, leading to a pressure-tunable increased conductivity.
New study gives compelling evidence that tungsten diphosphide is a type-II Weyl semimetal
Researchers at NCCR MARVEL have combined first principles calculations with soft X-ray angle-resolved photoemission spectroscopy to examine tungsten diphosphide’s electronic structure, characterizing its Weyl nodes for the very first time. In agreement with density functional theory calculations, the results revealed two pairs of Weyl nodes lying at different binding energies. The observation of the Weyl nodes, as well as the tilted cone-like dispersions in the vicinity of the nodal points, provides compelling evidence that the material is a robust type-II Weyl semimetal with broken Lorentz invariance. This is as MARVEL researchers predicted two years ago. The research has been published in Physical Review Letters as an Editor's Suggestion.
Prof. Helena Van Swygenhoven presented the plenary Kavli lecture at the MRS spring meeting 2019
Plenary Session Featuring The Fred Kavli Distinguished Lectureship in Materials Science:
Tuesday, April 23
8:15 am – 9:30 am
PCC North, 100 Level, Ballroom 120 D
Carlos Vaz Selected by the Journal of Materials Chemistry C as Outstanding Reviewer in 2018
SIM beamline scientist Carlos Vaz was recognized as outstanding referee for providing high quality peer review for the Journal of Materials Chemistry C (Royal Society of Chemistry).
X‐Ray Writing of Metallic Conductivity and Oxygen Vacancies at Silicon/SrTiO3 Interfaces
Lithography‐like writing of conducting regions at the interface between SrTiO3 and amorphous Si using X‐ray irradiation opens ways for spatially controlled functionalities in oxide heterostructures.
Terahertz-driven phonon upconversion in SrTiO3
Direct manipulation of the atomic lattice using intense long-wavelength laser pulses has become a viable approach to create new states of matter in complex materials. Conventionally, a high-frequency vibrational mode is driven resonantly by a mid-infrared laser pulse and the lattice structure is modified through indirect coupling of this infrared-active phonon to other, lower-frequency lattice modulations.
HERCULES school 2019 at SLS
In the week of April 1-5 PSI welcomes 20 PhD students and postdocs taking part in the European HERCULES 2019 school on Neutron and Synchrotron Radiation. They will attend lectures and perform two days of practical courses at several beam lines of the Swiss Light Source.
A new twist on a mesmerising story
The Einstein–de Haas effect, first demonstrated more than a century ago, provides an intriguing link between magnetism and rotation in ferromagnetic materials. An international team led by ETH physicist Steven Johnson now established that the effect has also a central role in ultrafast processes that happen at the sub-picosecond timescale — and thus deliver fresh insight into materials that might form the basis for novel devices.
Photoswitching in a Molecular Cube
Niéli’s paper is accepted in the Journal of Physical Chemistry Letters! We use X-ray absorption spectroscopy and X-ray magnetic circular dichroism to watch directly how the Co and Fe ions in a molecular cube change their oxidation states and turn from diamagnetic into paramagnetic units upon light irradiation.