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SIS - X09LA: Surface / Interface Spectroscopy
The Surface/Interface Spectroscopy (SIS) beamline provides a state-of-the-art experimental set-up to study the electronic band structure of novel complex materials by spin- and angle-resolved photoemission spectroscopies. The beamline operates in the energy range from 10 to 800 eV with high flux, high resolution, variable polarization, and low high-harmonic contamination.
The beamline serves two endstations:
- ULTRA (Ultra Low-Temperature high-Resolution ARPES)
for angle-resolved photoelectron spectroscopy (ARPES) - COPHEE (Complete PHotoEmission Experiment)
for spin- and angle-resolved photoelectron spectroscopy (SARPES)
Users can apply for beamtime with the provided endstations or with their own endstation (after prior consultation with the beamline scientist).
| Energy range | 10 - 800 eV |
|---|---|
| Resolving power (E/Δ E) | 104 |
| Polarization | linear horizontal (20 - 800 eV) linear vertical (100 - 800 eV) circular left/right (50-800 eV) |
| Flux on sample (200 eV) | 2*1013 ph/s/0.1%BW/0.4 A |
| Higher order mode contamination | < 0.1 % |
| Spot size on sample (200 eV) | 50 x 100 µm2 (FWHM) |
Current Highlights and News
Weyl fermions discovered in another class of materials
A particular variety of particles, the so-called Weyl fermions, had previously only been detected in certain non-magnetic materials. But now researchers at PSI have experimentally proved their existence for the first time in a specific paramagnetic material.
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.
Cuprate Trilogy
In a trio of recent papers, a research group from the University of Zürich has made a number of new discoveries about the nature of cuprates' electronic structure and orbital composition. The results have important implications for superconductivity and pseudogaps in cuprates, and even the existence of type-II Dirac fermions in oxides.