Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Correlated Electrons: Poster

TT 80.53: Poster

Donnerstag, 21. März 2024, 15:00–18:00, Poster E

Understanding the supercritical phase of the Hubbard model with timescales of the local moment screening — •Léo Gaspard^{1, 2} and Jan M. Tomczak^{2, 3} — ¹Laboratoire de Chimie et Physique Quantiques, Université Toulouse III - Paul Sabatier, Toulouse, France — ²Institut für Festkörperphysik, Technische Universität Wien, Wien, Austria — ³King’s College London, London, United Kingdom

A material’s phase diagram typically indicates the types of realized long-range orders, corresponding to instabilities in static response functions. In correlated systems, however, key phenomena crucially depend on dynamical processes, too: In a Mott insulator, the electrons’ spin moment fluctuates in time, while it is dynamically screened in Kondo systems. Here, we introduce a timescale "t_m" characteristic for the screening of the local spin moment and demonstrate that it fully characterizes the dynamical mean-field phase diagram of the Hubbard model: The retarded magnetic response delineates the Mott transition and provides a new perspective on its signatures in the supercritical region above. We show that "t_m" has knowledge of the Widom line and that it can be used to demarcate the Fermi liquid from the bad metal regime. Additionally, we identify a region with preformed local moments that we suggest to have a thermodynamic signature.

Keywords: Hubbard model; DMFT; Magnetic susceptibility