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TT: Fachverband Tiefe Temperaturen
TT 11: Heavy Fermions
TT 11.6: Talk
Monday, March 18, 2024, 16:30–16:45, H 3005
Paradigm for the search of d-electron heavy fermions: the case of Cr-doped CsFe2As2 — •Matteo Crispino1,2, Pablo Villar Arribi1,3, Anmol Shukla4, Frédéric Hardy4, Amir-Abbas Haghighirad4, Thomas Wolf4, Rolf Heid4, Christoph Meingast4, Tommaso Gorni1, Adolfo Avella5, and Luca de’ Medici1 — 1Laboratoire de Physique et Etude des Matériaux, UMR8213 CNRS/ESPCI/UPMC, Paris, France — 2Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany — 3International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy — 4Karlsruhe Institute of Technology, Institute for Quantum Materials and Technologies (IQMT), 76021 Karlsruhe, Germany — 5Dipartimento di Fisica "E. R. Caianiello", Università degli Studi di Salerno, I-84084 Fisciano, Italy
We define a general strategy to find new heavy-fermion materials without rare-earth elements: doping towards half-filling a Hund metal with pronounced orbital-selective correlations. We argue that in general bandstructures a possible orbital-selective Mott transition is frustrated by inter-orbital hopping into a heavy-fermion behaviour - with d-orbitals providing both heavy and light electrons - which is enhanced by approaching half-filling. This phase ultimately breaks due to magnetic correlations, as in a standard Doniach diagram. Experimentally we have hole-doped the Hund metal CsFe2As2, and obtained a heavy-fermion state with the highest Sommerfeld coefficient for Fe-pnictides to date (270 mJ/mol K2), before antiferromagnetism sets in.
Keywords: Heavy Fermions; Hund Metals; Mott Transition; Antiferromagnetism