Engineering quantum confinement and orbital couplings in laterally coupled vertical quantum dots for spintronic applications

We use three-dimensional self-consistent Kohn-Sham's equations coupled with Poisson's equation to investigate the electrical behavior of laterally coupled vertical quantum dots (LCVQD) for spin-qubit operation. The shape and the depth of the central gate are changed in different ways to correlate gate geometry with the coupling between the two quantum dots. Upon comparing LCVQD single-gate and the split-gate structures, we found that the two inherently different designs result in different energy barrier profiles leading to dissimilar wavefunction coupling between the two dots. Finally, we show that the doping concentrations in the layered structure could be optimized for practical two-qubit operation.