Kondo effect in Lieb's minimal 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 (London) 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 ${g}_{s}\ensuremath{\simeq}0$, while the parallel conductance ${g}_{p}$ has the maximum value ${g}_{p}\ensuremath{\simeq}4{e}^{2}/h$. 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.