Observation of the Kondo effect in a quadruple quantum dot

© 2015 American Physical Society.We investigate the Kondo effect in a quadruple-quantum-dot device of coupled double quantum dots (DQDs), which simultaneously contain intra-DQD and inter-DQD coupling. A variety of novel behaviors are observed. The differential conductance dI/dV is measured in the upper DQDs as a function of source drain bias. It is found to exhibit multiple peaks, including a zero-bias peak, where the number of peaks exceeds five. Alternatively, tuning the lower DQDs yielded regions of four peaks. In addition, a Kondo effect switcher is demonstrated, using the lower DQDs as the controller.