Toggling the Local Electric Field with an Embedded Adatom Switch

By means of scanning probe microscopy we demonstrate that Au+ on NaCl films adsorbs in an embedded, slightly off-centered Cl-Cl bridge position and can be switched between two equivalent mirror-symmetric configurations using the attractive force exerted by a scanning probe tip. Density functional theory calculations demonstrate that the displacement of the Au atom from the centered position of the bridge configuration is accompanied by a large lifting of the closest Cl atom leading to significant changes in the local electrostatic field. Our findings suggest that Au can be used to toggle the local electrostatic field.