Spectroscopy of Novel Materials Group
The Spectroscopy of Novel Materials group uses advanced spectroscopic techniques to study electronic structure, low-energy excitations and correlation effects in a broad range of complex material systems exhibiting surprising and useful properties. These include high-temperature superconductors, low-dimensional magnets, colossal magnetoresistors, topological insulators, oxide thin films, interfaces between oxide materials, and oxide heterostructures. We operate two beamlines with two endstations each.
The SIS beamline offers high-resolution angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES with photon energies in the VUV to soft X-ray regime (20-800 eV). The ADRESS beamline operates in the soft X-ray range (300-1600 eV) and hosts resonant inelastic x-ray scattering (RIXS) and soft x-ray ARPES endstations. Additionally, part of our research makes use of a dedicated pulsed laser deposition (PLD) chamber for in situ studies of thin films, interfaces, and heterostructures. Collectively, these techniques give us the ability to probe surface and bulk properties of complex materials and to visualize the interplay of the electrons with spin, lattice, and orbital degrees of freedom.
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.
Researchers at PSI have investigated a novel crystalline material at the Swiss Light Source SLS that exhibits electronic properties never seen before. Among other things, they were able to detect a new type of quasiparticle: so-called Rarita-Schwinger fermions.
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.