Dec, 2014
Time-resolved HAXPES at SACLA: probe and pump pulse-induced space-charge effects
NEW JOURNAL OF PHYSICS
- Volume
- 16
- Number
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1088/1367-2630/16/12/123045
- Publisher
- IOP PUBLISHING LTD
Time-resolved hard x-ray photoelectron spectroscopy (trHAXPES) is established using the x-ray free-electron laser SACLA. The technique extends time-resolved photoemission into the hard x-ray regime and, as a core-level spectroscopy, combines element and atomic-site specificity and sensitivity to the chemical environment with femtosecond time resolution and bulk (sub-surface) sensitivity. The viability of trHAXPES using 8 keV x-ray free-electron-laser radiation is demonstrated by a systematic investigation of probe and pump pulse-induced vacuum space-charge effects on the V 1s emission of VO2 and the Ti 1s emission of SrTiO3. The time and excitation energy dependencies of the measured spectral shifts and broadenings are compared to the results of N-body numerical simulations and simple analytic (mean-field) models. Good agreement between the experimental and calculated results is obtained. In particular, the characteristic temporal evolution of the pump pulse-induced spectral shift is shown to provide an effective means to determine the temporal overlap of pump and probe pulses. trHAXPES opens a new avenue in the study of ultrafast atomic-site specific electron and chemical dynamics in materials and at buried interfaces.
- Link information
- ID information
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- DOI : 10.1088/1367-2630/16/12/123045
- ISSN : 1367-2630
- Web of Science ID : WOS:000346822200003