摘要
Transition between quantum states in a double quantum dot (DQD) arising from strong electron and spin correlations was studied. A continuous transition from Kondo state, which exhibits a single peak Kondo resonance, to another exhibiting a double peak was observed, when the interdot coupling in the parallel-coupled DQD was increased. Evidence for spin entanglement between the excess electrons in each dot was provided by the transitions into the double-peak state. The peak splitting was found to merge and become substantially smaller than the interdot coupling because of strong Coloumb effects.