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arXiv · 2501.18325

Disentangling real space fluctuations: the diagnostics of metal-insulator transitions beyond single-particle spectral functions

Michael Meixner·Marcel Krämer·Nils Wentzell·Pietro M. Bonetti·Sabine Andergassen·Alessandro Toschi·Thomas Schäfer
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Abstract

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 are responsible for 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 $\lambda$ to the self-energy $\Sigma$. Second, by using cellular dynamical mean-field theory calculations for $\lambda$ we identify the leading physical processes responsible for the destruction of metallicity across the transition.

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Michael Meixner, Marcel Krämer, Nils Wentzell, Pietro M. Bonetti, Sabine Andergassen, Alessandro Toschi, Thomas Schäfer. 2025-01-30. Disentangling real space fluctuations: the diagnostics of metal-insulator transitions beyond single-particle spectral functions. https://doi.org/10.1103/1nt5-swsk

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