Scanning tunneling microscopy and spectroscopy of conjugated oligomers weakly bonded to Si(100) surfaces: A theoretical study

Abstract

We present theoretical simulations of the Scanning Tunneling Microscopy (STM) of thienylenevinylene oligomers physisorbed on a Si(100) surface. Calculations based on a tight-binding method including self-consistency for the molecule are used to predict STM imaging and spectroscopy. We obtain that the STM images in the constant current mode are characterized by several bumps which do not coincide with the thiophene rings in the molecule but reveal the dimer rows below the molecule. We show that this behavior does not depend on the size of the molecule, on its orientation with respect to the dimer rows, or on the buckling of the dimers. These results are discussed and compared with available experimental data.