Dinner
.
Loading view.
Latest Past Events
Corinna Burri: Spatial mapping of the electronic structure of 1T-TaS2
As a step towards resolving the spatially-resolved electronic structure of the layered transition metal dichalcogenide 1T-TaS2 – and eventually electronically switched cryomemory devices – we have performed angle-resolved photoemission spectroscopy (ARPES). Using a photon energy of 72 eV and the micrometer spot size available at the spectromicroscopy beamline of the Elettra synchrotron, we measured the band structure and high-statistics Fermi surface of 11, 500 and 600 nm thick flakes. Also, the first-order phase transition from the nearly-commensurate to the commensurate CDW state leads to a prominent splitting of the Ta 4f core levels which we have mapped spatially. In addition, using 400 eV soft X-ray ARPES at the ADRESS beamline of the Swiss Light Source synchrotron, we established the kz dependence of the band structure of a 110-nm thick flake, which reveals a two dimensionality of the electronic structure.
Simon Gerber: Direct characterization of photo- and electrically-induced “hidden” state switching of 1T-TaS2
Brilliant, ultrashort, and coherent X-ray free-electron laser (FEL) pulses allow for investigation of dynamics at the inherent time and length scale of atoms. I will illustrate this capability at the example of recent time-resolved X-ray diffraction data taken in the “hidden” phase of the Van der Waals material 1T-TaS2, hinting that out-of-plane restacking suppresses the optically-induced hidden state. Furthermore, I will also present preliminary static micro-beam X-ray diffraction data of electrically switched 1T-TaS2 cryomemory cells which indicate that also from a structural point of view the photo- and electrically-induced “hidden” states are closely related.
