0000000000235413
AUTHOR
Kai Rossnagel
Survival of Floquet–Bloch States in the Presence of Scattering
Floquet theory has spawned many exciting possibilities for electronic structure control with light, with enormous potential for future applications. The experimental demonstration in solids, however, remains largely unrealized. In particular, the influence of scattering on the formation of Floquet-Bloch states remains poorly understood. Here we combine time- and angle-resolved photoemission spectroscopy with time-dependent density functional theory and a two-level model with relaxation to investigate the survival of Floquet-Bloch states in the presence of scattering. We find that Floquet-Bloch states will be destroyed if scattering-activated by electronic excitations-prevents the Bloch elec…
Suppression of the vacuum space-charge effect in fs-photoemission by a retarding electrostatic front lens
Review of scientific instruments 92(5), 053703 (2021). doi:10.1063/5.0046567
Hard x-ray photoelectron spectroscopy: a snapshot of the state-of-the-art in 2020
Journal of physics / Condensed matter 33(23), 233001 (1-44) (2021). doi:10.1088/1361-648X/abeacd
Ultrafast Metamorphosis of a Complex Charge Density Wave in Tantalumdiselenite
Using ultrafast electron diffraction, we record the transformation between a nearly-commensurate and an incommensurate charge-density-wave in 1T-TaS2, which takes place orders of magnitude faster than previously observed for commensurate-to-incommensurate transitions.
Ultrafast Metamorphosis of a Complex Charge-Density Wave
Modulated phases, commensurate or incommensurate with the host crystal lattice, are ubiquitous in solids. The transition between such phases involves formation and rearrangement of domain walls and is generally slow. Using ultrafast electron diffraction, we directly record the photoinduced transformation between a nearly commensurate and an incommensurate charge-density-wave phase in 1T-TaS(2). The transformation takes place on the picosecond time scale, orders of magnitude faster than previously observed for commensurate-to-incommensurate transitions. The transition speed and mechanism can be linked to the peculiar nanoscale structure of the photoexcited nearly commensurate phase.