Nonlocal Kondo coupling and selective doping from cerium f electrons in iron-based superconductors

Abstract

In this paper, we consider an unconventional doping effect of strongly correlated cerium 4f 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.

Source-reported materials — not catalogue approval

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