Kondo effect in Lieb's ferrimagnetic system on the T-shaped bipartite lattice

Abstract

The minimal ferrimagnetism by Lieb's theorem emerges on the T-shaped bipartite lattice composed of four sites, which can be realized experimentally, just as Nagaoka ferromagnetism has been demonstrated experimentally using a quartet quantum-dot(J.P.Dehollain et al., Nature 579, 528 (2020).). In this paper, the Kondo effect on this ferrimagnetism is theoretically studied. The magnetic moment $S=1$ is screened in two steps by the Kondo effect and the series conductance $g_{s}$ is strongly suppressed to $g_{s}\simeq 0$, while the parallel conductance $g_{p}$ has the maximum value $g_{p}\simeq 4e^{2}/h$. The robustness of these properties against a parameter change toward reducing the Lieb's ferrimagnetism is also discussed, showing the scenarios for entanglement of the degrees of freedom toward the ground state.