title: Assessment of scanning tunneling spectroscopy modes inspecting electron confinement in surface-confined supramolecular networks.
abstract: Scanning tunneling spectroscopy (STS) enables the local, energy-resolved investigation of a samples surface density of states (DOS) by measuring the differential conductance (dI/dV) being approximately proportional to the DOS. It is popular to examine the electronic structure of elementary samples by acquiring dI/dV maps under constant current conditions. Here we demonstrate the intricacy of STS mapping of samples exhibiting a strong corrugation originating from electronic density and local work function changes. The confinement of the Ag(111) surface state by a porous organic network is studied with maps obtained under constant-current (CC) as well as open-feedback-loop (OFL) conditions. We show how the CC maps deviate markedly from the physically more meaningful OFL maps. By applying a renormalization procedure to the OFL data we can mimic the spurious effects of the CC mode and thereby rationalize the physical effects evoking the artefacts in the CC maps.
authors.affiliation: Physik Department E20, Technische Universität München, James-Franck Straße, 85748 Garching, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Krenner
authors.forename: Dirk
authors.initials: D
authors.lastname: Kühne
authors.forename: Florian
authors.initials: F
authors.lastname: Klappenberger
authors.forename: Johannes V
authors.initials: JV
authors.lastname: Barth