Scanning-gate-induced effects and spatial mapping of a cavity

Tailored electrostatic potentials are the foundation of scanning gate microscopy. We present several aspects of the tip-induced potential on the two-dimensional electron gas. First, we give methods on how to estimate the size of the tip-induced potential. Then, a ballistic cavity is formed and studied as a function of the bias-voltage of the metallic top gates and probed with the tip-induced potential. It is shown how the potential of the cavity changes by tuning the system to a regime where conductance quantization in the constrictions formed by the tip and the top gates occurs. This conductance quantization leads to a unprecedented rich fringe pattern over the entire structure. Finally, the effect of electrostatic screening of the metallic top gates is discussed.