screening the electrostatic attractive force is large enough to be sensed by the AFM. We observe this as an attractive force offset of ˜4 nN in the baseline when executing a single force curve on the substrate and toggling the applied potential at contact (supplementary SI-6). In the case where electrode separation is ≤ 2λ D (also been referred as double layer cross-talk), the electrochemical conditions in the gap are not well-defined and may lead to unconventional electrochemistry. The double layer overlap between an STM tip and metal substrate has been suggested to cause an enhanced local dissolution of the substrate while being held at a known potential, where no dissolution is expected. Particularly different in these works with respect to ours, is the much smaller gap sizes (<2 nm to ensure feedback from tunneling current) and the unlimited access to the solid metal atoms for the oxidation reaction.