The interesting implication of incomplete screening in the gap facilitated by the continuous disruption of the EDL, is that the tip and substrate effectively form a capacitor. In other words, the ions inside the gap are subject to a (linear) potential profile between the electrodes purely defined by gap size and bias voltage (Fig. ). In the limiting case of no free charges in the gap, the potential can be calculated by solving Laplace's equation. Considering the plane of closest approach for a solvated ion (0.6 nm arising from the size of the water molecule ), the solution potential at the interface is raised by ˜5% of the tip voltage at a 10 nm gap size, and up to ˜20% at 3 nm, as illustrated in Fig. . Since we typically use bias voltages up to ˜2 V, the unscreened tip perturbation can potentially increase the electrochemical potential of ions inside the gap by up to a a few hundred mV through direct electrostatic interaction. This effect greatly enhances the local charge transfer, as Faradaic currents exponentially increase with potential, but it quickly disappears as the tip moves away from the substrate.