Nonlocal Kondo coupling and selective doping from cerium f electrons in iron-based superconductors
Résumé
In this paper, we consider an unconventional doping effect of strongly correlated cerium 4 f electrons in layered intermetallic systems. The conduction electron part of the model is taken to reproduce the hole and electron pockets of iron-based superconductors (FeSCs), and the cerium contribution is studied through an effective tight-binding Hamiltonian arising from the slave-boson mean-field theory of the periodic Anderson model. We show how the consideration of the nonlocal Kondo coupling naturally present in real materials can lead to a pocket-selective doping effect from cerium f electrons. The model is designed for paramagnetic materials of the ZrCuSiAs-type structure such as CeFeSiH, CeFePO, or the high-pressure phase of CeFeAsO. In certain conditions, the model shows a Lifshitz transition which can be induced by either doping or change in the hybridization strength between iron and cerium orbitals. We present some signatures of both pocket-selective doping and Lifshitz transition by means of the density of states at the Fermi level, the static spin susceptibility, the optical conductivity, and Raman spectroscopy.
Domaines
Matériaux
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