Two-stage Kondo effect in a four-electron artificial atom
Two-stage Kondo effect in a four-electron artificial atom
An artificial atom with four electrons is driven through a singlet-triplet transition by varying the confining potential. In the triplet, a Kondo peak with a narrow dip at drain-source voltage ${V}_{\mathit{ds}}=0$ is observed. The low energy scale ${V}_{\mathit{ds}}^{*}$ characterizing the dip is consistent with predictions for the two-stage Kondo effect. …