Self-doping and the Mott-Kondo scenario for infinite-layer nickelate superconductors

TL;DR

This paper reviews the Mott-Kondo scenario in infinite-layer nickelate superconductors, proposing a self-doped Mott insulator model that explains their low-energy properties, resistivity behavior, and superconducting pairing symmetry transitions.

Contribution

It introduces an effective $t$-$J$-$K$ model for nickelates, explaining their unconventional superconductivity and non-Fermi liquid behavior through Kondo physics and doping effects.

Findings

Parent state is a self-doped Mott insulator.

Model predicts a breakdown of the Kondo effect with doping.

Superconductivity transitions from nodeless to nodal pairing near critical doping.

Abstract

We give a brief review of the Mott-Kondo scenario and its consequence in the recently-discovered infinite-layer nickelate superconductors. We argue that the parent state is a self-doped Mott insulator and propose an effective $t$-$J$-$K$ model to account for its low-energy properties. At small doping, the model describes a low carrier density Kondo system with incoherent Kondo scattering at finite temperatures, in good agreement with experimental observation of the logarithmic temperature dependence of electric resistivity. Upon increasing Sr doping, the model predicts a breakdown of the Kondo effect, which provides a potential explanation of the non-Fermi liquid behavior of the electric resistivity with a power law scaling over a wide range of the temperature. Unconventional superconductivity is shown to undergo a transition from nodeless $(d+is)$-wave to nodal $d$-wave near the critical doping due to competition of the Kondo and Heisenberg superexchange interactions. The presence of different pairing symmetry may be supported by recent tunneling measurements.