The present invention provides nano-patterning based on flow of an ion current within an ionic conductor to bring ions in proximity to a microscope probe tip touching a surface of the conductor. These ions are then electrochemically reduced to form one or more features on the surface. Ion current flow and the electrochemical reaction are driven by an electrical potential difference between the tip and the ionic conductor. Such features can be erased by reversing the polarity of the potential difference. Indentations can be formed by mechanically removing features formed as described above. The ions in the ion current can be provided by the ionic conductor and/or by oxidation at a counter electrode.