Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 4: Electronic Structure of Surfaces I
O 4.1: Vortrag
Montag, 16. März 2015, 10:30–10:45, MA 041
Phonon-Mediated Electron Transport through CaO Thin Films — •Niklas Nilius1, Yi Cui2, and Hans-Joachim Freund2 — 1Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg, Germany — 2Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
Scanning tunneling microscopy has developed into a powerful tool for the characterization of conductive surfaces, for which the overlap of tip and sample wavefunctions determines the image contrast. On insulating layers, as the CaO thin-film grown on Mo(001) investigated here, direct overlap between initial and final states is not possible anymore and electrons are transported via hopping through the conduction-band states of the oxide. In this case, carrier transport is accompanied by strong phonon excitations, imprinting an oscillatory behavior onto the differential conductance of the system. The phonons show a characteristic spatial dependence and become softer around lattice irregularities in the oxide film, such as dislocation lines.