Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: Other Theoretical Topics
TT 43.4: Vortrag
Donnerstag, 20. März 2025, 10:15–10:30, H33
Disentangling real space fluctuations: The diagnostics of metal-insulator transitions beyond single-particle spectral functions — •Michael Meixner1, Marcel Krämer1,2, Nils Wentzell3, Pietro Bonetti1,4, Sabine Andergassen2, Alessandro Toschi2, and Thomas Schäfer1 — 1Max-Planck-Insitut für Festkörperforschung, Stuttgart, Germany — 2TU Wien, Vienna, Austria — 3CCQ at Flatiron Institut, New York NY, USA — 4Harvard University, Cabridge MA, USA
The destruction of metallicity due to the mutual Coulomb interaction of quasiparticles gives rise to fascinating phenomena of solid state physics such as the Mott metal-insulator transition and the pseudogap. A key observable characterizing their occurrences is the single-particle spectral function, determined by the fermionic self-energy. In this paper we investigate in detail how real space fluctuations constitute a self-energy that drives the Mott-Hubbard metal-insulator transition. To this aim we first introduce a real space fluctuation diagnostics approach to the Hedin equation, which connects the fermion-boson coupling vertex λ to the self-energy Σ. Second, by using cellular dynamical mean-field theory calculations for λ we identify the leading physical processes responsible for the destruction of metallicity across the transition. Eventually, to pave the way for relating our findings to the pseudogap phenomenology, we discuss the influence of real space fluctuations on the momentum-dependence of correlations.
Keywords: Metal-Insulator transition; Mott insulator; Cellular dynamical mean field theory; Antiferromagnetic fluctuations; Fermion-boson response