Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: Other Theoretical Topics
TT 43.1: Vortrag
Donnerstag, 20. März 2025, 09:30–09:45, H33
Fragility of local moments for singular hybridizations — •Max Fischer1,2, Arianna Poli3, Lorenzo Crippa1,2, Sergio Ciuchi3,4, Matthias Vojta2,5, Alessandro Toschi6, and Giorgio Sangiovanni1,2 — 1Universität Würzburg, Germany — 2Würzburg-Dresden Cluster of Excellence ct.qmat — 3Università dell’Aquila, Italy — 4CNR, Italy — 5TU Dresden, Germany — 6TU Wien, Austria
Some transition-metal phtalocyanines on an Ag(001) surface show hybridizations for xz/yz-orbitals with sharp peaks superimposed on a rather constant z2 contribution. These sharp peaks in the hybridization correspond to an Anderson impurity model with one impurity site hybridized with one bath site. Investigating only a constant hybridization this typically shows rich physics arising from the Kondo effect yielding local moments and screening of them at low temperatures. Expanding the constant hybridization by a peak at the Fermi level, the formation of the local moment is shifted to lower temperatures with increasing weight of the peak. With such a toy model we analyze the vanishing of the local moment at large weights of the peak. Here, we find the evolution from screening of the local moment to the formation of a singlet ground state for the two site AIM.
Keywords: Kondo effect; Hybridization function; Anderson impurity model; Quantum Monte-Carlo