Electric-Field-Induced Molecular Switch of Single Dipolar Phthalocyanine on Cu(111): A Scanning Tunneling Microscopy Study

We demonstrate a molecular switch of a single Cl-down adsorbed choloraluminum phthalocyanine (ClAlPc) molecule on a Cu(111) substrate by scanning tunneling microscopy (STM) at liquid nitrogen temperature (77 K). The Cl-down adsorbed ClAlPc molecule exhibits an in-plane quadruple moment on the four-lobe which stems from the inequivalent charge distribution after anchoring on Cu(111). The quadruple moment under the nonuniform electric field between the STM tip and the sample surface is responsible for the rotation of these Cl-down adsorbed ClAlPc molecules within three metastable states. In response to the local nonuniform electric field, the switching of these Cl-down adsorbed ClAlPc molecules can be controlled by varying the applied biases. (Figure Presented).