Jorg Kroger
Technical University of Ilmenau, Germany
Title: Manipulating and characterizing matter at the atomic scale
Biography
Biography: Jorg Kroger
Abstract
The scanning tunnelling microscope (STM) enables imaging of surfaces with atomic precision, the spectroscopy of electronic states and vibrational quanta with high energy resolution and the manipulation of matter at the single-atom and single-molecule level. Combining these opportunities in a single experiment is particularly appealing. Th is study will present two examples. The local injection of electrons into a single phthalocyanine molecule adsorbed on graphene-covered Ir(111) induces the abstraction of pyrrolic hydrogen. While the geometric confi guration of the molecule stays invariant, its electronic structure changes considerably. The combination of STM data and density functional calculations unravels the entire depopulation of the highest occupied molecular orbital upon the single-molecule reaction. A new view on electron confi nement at metal surfaces is provided by scanning tunnelling spectroscopy (STS) a top buried nano-cavities at Pb(111). Diff erential conductance data measured by STS show signatures of vertically confined quantum well states. Characteristic spectroscopic fi ne structure reveals additional quantization, which unexpectedly arises from quantum well refl ection at the open boundary where the thin Pb fi lm above the nano-cavity recovers its bulk thickness. Lateral confinement is thus achieved without confi ning potential.