Tunable Kondo and Fano resonances in artificial quantum dot molecules

Abstract

Fully tunable artificial semiconductor double quantum dots coupled in series are fabricated using split-gate technique. Our devices are small enough to be in the Kondo regime for both dots and exhibit tunable magnetic Kondo molecule states. We observe unique appearance of the Kondo resonances in the two-dot system, which is consistent with recent theoretical studies. Our double quantum dot devices also showed Fano type asymmetric Coulomb blockade peaks that are tunable by changing gate voltages in a single cool-down. This demonstrates the interference phenomena in a strongly interacting system can be managed via in-situ control parameters.