Quantum transport through STM-lifted single PTCDA molecules

摘要

Using a scanning tunneling microscope we have measured the quantumconductance through a PTCDA molecule for different configurations of thetip-molecule-surface junction. A peculiar conductance resonance arises at theFermi level for certain tip to surface distances. We have relaxed the molecularjunction coordinates and calculated transport by means of the Landauer/Keldyshapproach. The zero bias transmission calculated for fixed tip positions inlateral dimensions but different tip substrate distances show a clear shift andsharpening of the molecular chemisorption level on increasing the STM-surfacedistance, in agreement with experiment.