Me-Phthalocyanine (MePc) molecules have potential applications as switches in molecular electronics. Recent experiments performed by the group of R. Berndt at the University Kiel indicate that SnPc can be changed between an in-plane and an out-of-plane conformation by means of STM induced tunneling. To control this switching it is crucial to understand the underlying transport mechanism.
We have studied the electronic transport properties of structural conformations of various MePc molecules on a Au(111) surface. In particular, the possibility of switching the larger metal atoms in an STM experiment between an in-plane and an out-of-plane conformation has been investigated. We used an STM-tip/molecule/surface configuration in order to work out which transport regime could induce this shift. The electronic transport properties and the geometry of the system were calculated for different applied bias voltages. We also investigated the variation of the transport characteristics through the MePc molecule with increasing current.