Dresden 2017 – wissenschaftliches Programm
MM 13: Electronic Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - II
MM 13.4: Vortrag
Montag, 20. März 2017, 16:00–16:15, GER 38
Addressing electron-hole correlation in core excitations of solids: A first-principles all-electron approach based on many-body perturbation theory — •Christian Vorwerk, Caterina Cocchi, and Claudia Draxl — Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
In the framework of an all-electron implementation of many-body perturbation theory, we investigate K, L2,3, and M4 absorption edges of three exemplary solids, spanning a broad range of transition energies from a few hundred to several thousands eV. We find that transitions from deep core states, such as the Ti 1s states in TiO2 and the Pb 3d states in PbI2, are ruled by the long-range electron-hole attraction. Spin-orbit coupling and local fields play only a minor role for these excitations, which occur at several keV. The exchange interaction between the excited electron and the core hole becomes more relevant for smaller transition energies, as exemplified with the Ca L2,3 edge in CaO. The overlap between Ca 2p and 3d states calls for a careful treatment of local field effects in order to describe these excitations. Our results, in good agreement with the available experimental data, are thoughtfully analyzed with advanced visualization tools in order to further gain insight into the electronic contributions and the spatial extension of the resulting electron-hole pairs.