Ultrafast Dynamics in solids probed by time-resolved XUV-ARPES
Date | Di, 31.05.2016 | |
Time | 11.00 | |
Speaker | Michael Bauer, Institute of Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany | |
Location | ETH Science City, HPF G6 | |
Program | Time- and angle-resolved photoemission spectroscopy is the potentially most direct and comprehensive, energy- and momentum-selective probe of ultrafast processes in solids that couple to the electronic degrees of freedom. Angular resolution enables one in this context to monitor the temporal evolution of the valence electronic band structure of a solid at selected - and possibly critical - points in momentum space [1]. The application of XUV photon pulses enlarges the accessible momentum regime considerably so that band structure transients within the entire Brillouin zone can be recorded [2, 3]. In this contribution some recent results on the ultrafast dynamics in solids as probed by time-resolved XUV-ARPES will be presented. Examples include hot electron dynamics in graphite [3], ultrafast melting processes of charge-ordered phases in transition metal dichalcogenides [4, 5], and coherent phonon dynamics in the iron-pnictide BaFe2As2 [6]. References [1] F. Schmitt et al., “Transient Electronic Structure and Melting of a Charge Density Wave in TbTe3” Science 321, 1649 (2008). [2] S. Mathias et al., “Angle Resolved Photoemission Spectroscopy with a Femtosecond High Harmonic Light Source using a 2D Imaging Electron Analyzer” Rev. Sci. Instr. 78, 083105 (2007). [3] A. Stange et al., “Hot Electron Cooling in Graphite: Supercollision versus Hot Phonon Decay” Phys. Rev. B 92, 184303 (2015). [4] T. Rohwer et al., “Collapse of long-range charge order tracked by time-resolved photoemission at high momenta” Nature 471, 490 (2011). [5] S. Hellmann et al., „Time-domain classification of charge-density-wave insulators” Nat. Commun. 3, 1069 (2012). [6] L. X. Yang et al., „Ultrafast modulation of the chemical potential in BaFe2As2 by coherent phonons”, Phys. Rev. Lett. 112, 207001 (2014). |