Parallel-coupled Double Quantum Dot Research Articles

Properties of the ground state of parallel double quantum dots embedded in a mesoscopic ring

We theoretically study the properties of the ground state of the parallel-coupled double quantum dot embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. Our results that when the system goes into the strong coupling regime, two parallel dots can are coupled coherently, which leads to an enhanced Kondo effect and a giant persistent current emerging in this system. This double quantum dot device might be a possible candidate for future device applications.

Transition between quantum states in a parallel-coupled double quantum dot.

Strong electron and spin correlations in a double quantum dot (DQD) can give rise to different quantum states. We observe a continuous transition from a Kondo state exhibiting a single-peak Kondo resonance to another exhibiting a double peak by increasing the interdot coupling (t) in a parallel-coupled DQD. The transition into the double-peak state provides evidence for spin entanglement between the excess electrons on each dot. Toward the transition, the peak splitting merges and becomes substantially smaller than t because of strong Coulomb effects. Our device tunability bodes well for future quantum computation applications.