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OnderzoekZernike (ZIAM)NewsSeminars

Lecture M. Trigo


04 september 2009 FWN-Building 5118.-152, Nijenborgh 4, 9747 AG, Groningen
Speaker: Dr. M. Trigo
Affiliation: SLAC National Accelerator Laboratory, USA
Title: Time-resolved X-ray diffuse scattering from non-equilibrium phonons in solids
Date: Fri Sep 4, 2009
Start: 11.00
Location: FWN-Building 5118.-152
Host: P.H.M. van Loosdrecht
Telephone: +31 50 363 8149


Intense, ultra-short laser pulses are currently used to study a wide range of coherent as well as incoherent excitations in solids. However, visible and infrared radiation can only probe a reduced fraction of the Brillouin zone near the zone center and hence do not provide direct information on shorter range interactions. With the availability of ultra-intense and ultra-short x-ray pulses as 4th generation x-ray free-electron lasers come online, time-resolved x-ray diffuse scattering has the potential to be the ultimate tool to study excitations and their decay channels throughout the Brillouin zone. In this talk I will review my research using existing storage ring based sources to study picosecond time-resolved x-ray diffuse scattering by phonons in bulk semiconductors and their heterostructures. I will show how high wavector coherent acoustic modes can be generated via unfolding of zone-center acoustic modes at a superlattice/bulk interface and how these modes are detected with x-ray pulses.  I will then present measurements of the generation and decay of incoherent phonons throughout the Brillouin zone in bulk semiconductors as well as single-shot measurements of ultrafast melting and recrystallization in bimuth. Finally, I will discuss some of the unique challenges these experiments present and how this is shaping potential future scientific directions at 4th generation sources.

Laatst gewijzigd:22 oktober 2012 14:30