Engineering Exchange Coupling in Double Elliptic Quantum Dots

Abstract

Coupled elliptic quantum dots with different aspect ratios containing up to two electrons are studied using a model confinement potential in the presence of magnetic fields. Single and two particle Schroedinger equations are solved using numerical exact diagonolization to obtain the exchange energy and chemical potentials. As the ratio between the confinement strengths in directions perpendicular and parallel to the coupling direction of the double dots increases, the exchange energy at zero magnetic field increases, while the magnetic field of the singlet-triplet transition decreases. By investigating the charge stability diagram, we find that as inter-dot detuning increases, the absolute value of the exchange energy increases superlinearly followed by saturation. This behavior is attributed to the electron density differences between the singlet and triplet states in the assymetric quantum dot systems.

5 pages, 5 figures

References in corpus (7)

• Quantum Computation with Quantum Dots
• Electron transport through double quantum dots
• Coupled quantum dots as quantum gates
• Hilbert space structure of a solid state quantum computer: two-electron states of a double quantum dot artificial molecule
• Two-electron quantum dot molecule: Composite particles and the spin phase diagram
• Single-electron charging and detection in a laterally-coupled quantum dot circuit in the few-electron regime
• Exchange interaction and stability diagram of coupled quantum dots in magnetic fields

Cited by in corpus (2)

• Failure of standard approximations of the exchange coupling in nanostructures
• Tuning the exchange interaction by electric field in laterally coupled quantum dots