Three-dimensional self-consistent modelling of spin-qubit quantum dot devices

The electronic properties of devices based on double and triple quantum dots are studied numerically with an emphasis on their application for quantum computation. Simulations were conducted within the self-consistent multiscale approach where electrons in quantum dots are treated within the density-functional theory, while the semi-classical Thomas-Fermi model is used for outside regions. This approach allows fundamental description of quantum dot properties without any a priori assumptions, and at the same time, it provides new computer-aided design (CAD) methodologies suitable for optimisation of device performance. The authors apply this method to obtain stability diagrams for two laterally coupled quantum dots. Preliminary analysis of the singlet-triplet energy separation in a two-electron system is also given. The effect of different designs on the sensitivity of quantum point contacts is then considered. The charging diagram of the novel triple vertically coupled quantum dot structure with up to four electrons is also investigated.