Conference Presentation (Invited)

FZJ-2023-03530

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Electron-Magnon Scattering in Elementary Ferromagnets

Blügel, S.FZJ*

2023

Abstract: I report on the combination of two powerful self-energy techniques: the well-known GW method and a self-energy recently developed by us that describes renormalization effects caused by the scattering of electrons with magnons and Stoner excitations. This GT self-energy [1], which is fully k-dependent and contains infinitely many spin-flip ladder diagrams T [2], was shown to have a profound impact on the electronic band structure of Fe, Co, and Ni [3, 4]. In the presentation, I present the refinement of the method by combining GT with the GW self-energy. The resulting GWT spectral functions [5] exhibit strong lifetime effects and emergent dispersion anomalies. They are in an overall better agreement with experimental spectra than those obtained with GW or GT alone, even showing partial improvements over local-spin-density approximation dynamical mean-field theory [3]. According to our analysis, this method provides a basis for applying the GWT technique to a wider class of magnetic materials. By comparing spin- and momentum-resolved photoemission spectroscopy measurements to these many-body calculations we found a surprising kink in the electronic band dispersion of a ferromagnetic material at much deeper binding energies than ever expected (Eb = 1.5 eV).

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (PGI-1)
2. Quanten-Theorie der Materialien (IAS-1)
3. JARA - HPC (JARA-HPC)
4. JARA-FIT (JARA-FIT)

Research Program(s):

1. 5211 - Topological Matter (POF4-521) (POF4-521)

Appears in the scientific report 2023

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