Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 2: Ultrafast phenomena

HL 2.1: Vortrag

Montag, 11. März 2013, 09:30–09:45, H2

Ultrafast electron diffraction: Visualization of atomic motion in 4D — •Peter Baum — Max-Planck-Institute of Quantum Optics, and Ludwig-Maximilians-Universität München, Germany

The pathways of transitions in materials and molecules are determined by the motions of atoms and electron densities, on Angstrom scales and in femtosecond or attosecond times. We provide here an account of how ultrashort electron pulses can be used to obtain a four-dimensional visualization in space and time. At two examples, the insulator-metal phase transformation in VO₂ [1] and the interlayer dynamics of graphite [2], we demonstrate the resolution of coherent and incoherent atomic displacements with picometer and femtosecond resolution, indicating the sequential nature of atomic motion in condensed matter transitions. Electron densities can move in times as short as attoseconds. Single-electron pulses [3] afford some promise to reach into this novel regime [4]; we will discuss our approaches and what discoveries we may expect to see [5-6].

[1] Baum, Yang, Zewail, Science 318, 788 (2007)

[2] Carbone, Baum, Rudolf, Zewail, PRL 100, 035501 (2008)

[3] Aidelsburger, Kirchner, Krausz, Baum, PNAS 107, 19714 (2010)

[4] Baum and Zewail, PNAS 104, 18409 (2007)

[5] Baum and Zewail, Chem. Phys. 366, 2-8 (2009)

[6] Baum, Manz, Schild, Sci. China 53, 987 (2010)