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Wochenprogramm 29.1.2018 – 4.2.2018
Prof. Dr. Regina Palkovits (RWTH Aachen)
Material concepts for the valorization of renewable feedstocks
Chemisches Kolloquium, Raum: T-1004
Dr. Andrés Cano (CNRS, Université Grenoble Alpes, Institut Néel, Grenoble and Department of Materials, ETH Zurich)
FeSi: A new building block for iron-based superconductivity
Sonderseminar TRR80, Raum: S-288
Prof. Dr. Ferdi Aryasetiawan (Lund University, Sweden)
Reinterpretation of spectral functions of correlated metals SrVO3 and SrMoO3 according to self-consistent GW+DMFT

The spectral function or density of states of a typical correlated metal is often characterised by a three-peak structure: a quasiparticle peak around the Fermi level sandwiched by two satellite features. These satellite features are usually interpreted as Hubbard bands, which are understood within an atomic picture as arising from a strong onsite Coulomb interaction. We have studied the spectral functions of SrVO3, a prototype of correlated metals as well as SrMoO3 using a newly developed fully self-consistent GW+DMFT scheme. Analysis of the results reveals that the satellite features are better understood as collective plasmon excitations. This conclusion is reached by the finding that after self-consistency is achieved the impurity Hubbard U is substantially screened by the non-local Coulomb interaction and is much smaller than the energy separation between the two satellites, indicating that the conventional Hubbard-band interpretation may not be appropriate. We have also studied a model sodium in which the lattice constant is artificially increased to mimic correlation strength. Indeed, the collective plasmon picture also applies until the lattice constant reaches 1.5 the equilibrium value, at which stage the system turns into a Mott-Hubbard insulator. The present study suggests that the Hubbard band picture may need to be revised in favour of the plasmon picture for a much larger range of correlation strength than what has usually been assumed.

References: [1] L. Boehnke, F. Nilsson, F. Aryasetiawan, and P. Werner, Phys. Rev. B 94, 21106(R) (2016). [2] F. Nilsson, L. Boehnke, P. Werner, and F. Aryasetiawan, Phys. Rev. Mat. 1, 043803 (2017).

Lehrstuhlseminar Theoretische Physik III, Raum: S-439