ESPCI web site
June 19 at 2:00 pm (Paris time)
Room Boreau, building C, 2nd floor
Paradigm for Finding d-Electron Heavy Fermions : The Case of Cr-doped CsFe2As2
Ecole de Physique et Chimie Industrielle de la Ville de Paris (ESPCI), Paris, France
We define a general strategy for finding new heavy-fermionic materials without rare-earth elements : doping a Hund metal with pronounced orbital-selective correlations towards half- filling. We argue that in general band structures, a possible orbital-selective Mott transition is frustrated by interorbital hopping into heavy-fermion behavior - where d orbitals provide both the heavy and the light electrons - which is enhanced when approaching half-filling. This phase ultimately disappears due to magnetic correlations, as in a standard Doniach diagram. Experimentally we have hole doped CsFe2As2, a Hund metal with 0.5 electrons/Fe away from half-filling, and obtained a heavy fermionic state with the highest Sommerfeld coefficient for Fe pnictides to date (270 mJ/mol Kˆ2), before signatures of an antiferromagnetic phase set in.
Crispino et al., Phys. Rev. Lett. 134, 076504 (2025), https://physics.aps.org/articles/v18/s15
