B7: Imaging of short-range correlations at oxide surfaces and interfaces
Several electron pair emission experiments at oxide surfaces demonstrated that the coincidence signal provides a qualitative view of the strength and nature, e.g. symmetry, of the electron correlation. From the theoretical point of view new aspects have emerged which are the focus of the experimental and theoretical investigations in the new funding period.
The power of coincidence spectroscopy lies in the fact that it enables to map the energy and momentum dependence of the electron correlation which includes the non-local and dynamic properties. In the new funding period we plan experiments of this aspect in metal/oxide layer systems. The experiments are supported by theoretical calculations which include the electron correlation completely.
Collective excitations (e.g. plasmons) play conceptually a different role in a one photon-two electron process compared to a single electron process. Within the dipole photo excitation it is in principle possible that volume plasmon modes are accessible. Experiments and numerical calculations on metal/oxide structures are planned to validate this formal prediction.
In a first theoretical work we demonstrated that the time-resolved coincidence spectroscopy can provide non-local information on the time evolution of the spectral function. However, this statement was confined to times immediately after the excitation. By using quantum kinetics we want to extend the theory to finite times. At the same time we want to explore new experimental methods to test whether time-resolved coincidence spectroscopy is feasible.
Principal Investigators
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PD Dr. Frank Schumann ⇒
phone: +49 (0) 345/55 82616 fax: +49 (0) 345/55 11223 |
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Prof. Dr. Jürgen Kirschner ⇒
phone: +49 (0) 345/55 82655 fax: +49 (0) 345/55 11223 |
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Prof. Dr. Jamal Berakdar
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jamal.berakdar@physik.uni-halle.de phone: +49 (0) 345/55 28530 fax: +49 (0) 345/55 27391 |
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