ISBN 9783843906647

978-3-8439-0664-7, Reihe Physik

Sandra Sobczyk
STM transport theory for pi-conjugated molecules on thin insulating films

109 Seiten, Dissertation Universität Regensburg (2012), Softcover, A5

Zusammenfassung / Abstract

Based on the density matrix formalism, a microscopic theory of the transport in a scanning tunnelling microscope (STM) set-up is introduced for pi-conjugated molecules on insulating films. We analyze how the geometrical differerences between the localized tip and the extended substrate are encoded in the energy dependent tunnelling rates, which account for the coupling of the molecule to the leads. Thus it turns out that the lead geometry influences the transport characteristics drastically.

Considering rotationally symmetric molecules with orbitally degenerate many-body states negative differential conductance (NDC) can be ascribed to interference effects. We establish a criterion to identify the interference blocking scenario by correlating the spectral and the topographical information achievable in an STM single molecule measurement.