Hard X-Ray K-Microscope

Top: kx-ky equal energy cut trough the valence band close to the Fermi level for a Rhenium surface measured at 4.2keV.
Bottom: Cut a fixed k|| shows a clear dispersion of the valence band states

Medjanik, K. et al.
ArXiv:1810.11366 [Cond-Mat] (2018)
[http://arxiv.org/abs/1810.11366]

Experiments with the k-Microscope are still in the test phase and are run exclusively in collaboration with the Group of Gerd Schönhense from University Mainz. Please get in touch with the beam line staff to discuss wether its feasible to submit a proposal!

Photoelectron k-microscopy is a novel approach to obtain detailed information of the valence electronic structure. Angle- or momentum-resolved HAXPES is an emergent powerful tool for bulk electronic structure mapping. Full-field k-imaging with ToF energy recording provides maximum possible parallelization in data acquisition.The setup at P22 is a high-energy prototype of such an instrument with up to 20 Å-1 field of view . It combnes a PEEM immersion lens with a time-of-flight (ToF) drift tube for energy filtering, and is currently being commissioned. Additionally, an imaging spin filter is currntly under development to provide k-resolved spin textures.

This instrument is taking full advantage of the time structure of the reduced bunch filling modes of PETRA III, offering bunch separation of up to 192 ns (with 40 bunches) owing to the large circumference of the storage ring (2.3 km). It can be expected that k-microscopy will develop its full potential in the several-keV range, particularly for the study of the valence band structure of buried layers and interfaces.

Please also refer to the recent publication:
Medjanik, K. et al.
ArXiv:1810.11366 [Cond-Mat] (2018)
[http://arxiv.org/abs/1810.11366]