C. Nacci, K. Kanisawa, S. Fölsch

J. Phys. Condensed Matter (2012) accepted for publication

 

Abstract: Individual tin phthalocyanine (SnPc) molecules adsorbed on the InAs(111)A surface were studied by low-temperature scanning tunnelling microscopy (STM) at 5 K. Consistent with the nonplanar molecular structure, SnPc adopts two in-plane adsorption geometries with the centre Sn atom either above (SnPc_up) or below (SnPc_down) the molecular plane. Depending on the current and bias applied to the tunnel junction, the molecule can be reversibly switched between the two conformations, implying a controlled transfer of the Sn atom through the molecular plane. The SnPc_down conformer is characterized by an enhanced surface bonding compared to the SnPc_up conformer. SnPc_up molecules can be repositioned by the STM tip by means of lateral manipulation, whereas this is not feasible for SnPc_down molecules. The reversible switching process thus enables to either laterally move the molecule or to anchor it to the semiconductor surface.