Science@FELs 2018

Session

Condensed matter

26 Jun 2018, 11:30

Oskar Klein Auditorium (Stockholm, Alba Nova)

Conveners

Condensed matter

• Stefano Bonetti (Stockholm university)

Condensed matter

• Stefano Bonetti (Stockholm university)

77. [L] Transient electronic structure and spin polarization in lanthanide metals

Martin Weinelt (Freie Universitaet Berlin)

26/06/2018, 11:30

Invited oral (Laser)

On which timescale do the band structure and spin polarization of a ferromagnet change after femtosecond laser excitation and how do they affect the magnetization dynamics? To answer these questions we perform time-, spin-, and angle-resolved photoemission experiments with optical laser pulses and higher-order harmonic radiation.
We have studied ultrafast demagnetization in the local-moment...

83. In search for the phonon mean free path with optical, EUV and x-ray time-resolved measurements

Alexei Maznev (Department of Chemistry, MIT)

26/06/2018, 12:00

Invited oral

In non-metallic solids, heat is carried primarily by acoustic phonons. At cryogenic temperatures, the phonon mean free path (MFP) can be large, and ballistic propagation of heat over macroscopic distances has been well documented in the “phonon imaging” studies. At room temperature, the MFP of thermal phonons is small and heat typically propagates via diffusion: once the thermal conductivity...

19. Time-resolved photoemission spectroscopy at free-electron lasers

Kai Rossnagel (CAU Kiel and DESY)

26/06/2018, 13:30

Invited oral

Free-electron lasers (FELs) are currently the only ultrashort-pulsed photon sources that can provide sufficient photon flux for time-resolved pump-probe solid-state photoemission measurements in the soft and hard x-ray regime. In principle, FELs enable powerful combinations of photoemission techniques, augmented by femtosecond time resolution, in a single experiment. We particularly envision a...

80. Femtosecond electron-phonon lock-in in FeSe via ultrafast x-ray scattering and photoemission

Simon Gerber (Paul Scherrer Institut)

26/06/2018, 14:00

Invited oral

Identifying the degrees of freedom that lead to the emergence of superconductivity in iron-based materials remains the subject of active research. Amongst spin-driven scenarios, it has also been suggested that electron-electron correlations enhance the electron-phonon coupling in iron chalcogenides and related pnictides, but direct experimental verification has been lacking.

Measurements of...

20. Ultrafast manipulation of the structure and topological properties of layered materials

Aaron Lindenberg (Stanford University / SLAC)

26/06/2018, 14:30

Invited oral

I will describe recent experiments using ultrafast electron diffraction and x-ray free electron lasers to probe light-induced structural dynamics in layered transition metal dichalcogenide materials. In particular the focus of this talk will be terahertz-driven atomic-scale responses in WTe2 and related materials. We show, via the measurement of structure factor changes in >200 Bragg...