Electroisomerization blinking of an azobenzene derivative molecule

We report here the reversibility and bistability of the switching behavior in an azobenzene derivative induced by the bias applied by a scanning-tunneling microscopy (STM) tip, at low temperature and in ultra-high vacuum environment. This to- and to- switching were observed during STM imaging in either polarity at +2 V or -2 V, on a sub-second time scale. This results in a blinking effect visible on STM images, corresponding to the reversible switching of the azobenzene molecule under the applied STM bias through an electric field induced process.