تقرير
Momentum-Transfer Model of Valence-Band Photoelectron Diffraction
| العنوان: | Momentum-Transfer Model of Valence-Band Photoelectron Diffraction |
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| المؤلفون: | Schoenhense, G., Medjanik, K., Babenkov, S., Vasilyev, D., Ellguth, M., Fedchenko, O., Chernov, S., Schoenhense, B., Elmers, H. -J. |
| سنة النشر: | 2018 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Materials Science |
| الوصف: | Owing to strongly enhanced bulk sensitivity, angle- or momentum-resolved photoemission using X-rays is an emergent powerful tool for electronic structure mapping. A novel full-field k-imaging method with time-of-flight energy detection allowed rapid recording of 4D (EB,k) data arrays (EB binding energy; k final-state electron momentum) in the photon-energy range of 400-1700eV. Arrays for the d-band complex of several transition metals (Mo, W, Re, Ir) reveal numerous spots of strong local intensity enhancement up to a factor of 5. The enhancement is confined to small (EB,k)-regions (dk down to 0.01 A-1; dEB down to 200 meV) and is a fingerprint of valence-band photoelectron diffraction. Regions of constructive interference in the (EB,k)-scheme can be predicted in a manner resembling the Ewald construction. A key factor is the transfer of photon momentum to the electron, which breaks the symmetry and causes a rigid shift of the final-state energy isosphere. Working rigorously in k-space, our model does not need to assume a localization in real space, but works for itinerant band states without any assumptions or restrictions. The role of momentum conservation in Fermi's Golden Rule at X-ray energies is revealed in a graphical, intuitive way. The results are relevant for the emerging field of time-resolved photoelectron diffraction and can be combined with standing-wave excitation to gain element sensitivity. Comment: 24 pages, 7 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/1806.05871 |
| رقم الأكسشن: | edsarx.1806.05871 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |