Few-electron spin and charge configurations in circular and rectangular vertical quantum dot mesas in a magnetic field: Experiment and full three-dimensional self-consistent simulations

We explore the spin and charge properties as the shape of a single vertical quantum dot mesa is changed from being circular to rectangular. The magnetic field dependence of the electrochemical potentials of both mesa geometries is measured and compared with a full three-dimensional multi-scale self-consistent approach without any prior assumptions about the shape and strength of the dot confinement potential. The calculated zero field electron addition energies are in good agreement with experimental data for both mesa geometries. Few-electron charging diagrams in a magnetic field are also computed. Consistent with the experimental data, the charging curves for the rectangular mesa dot in a magnetic field are “flatter” and exhibit less features than for a circular mesa dot.