title: Nanometer-resolved mechanical properties around GaN crystal surface steps.
abstract: The mechanical properties of surfaces and nanostructures deviate from their bulk counterparts due to surface stress and reduced dimensionality. Experimental indentation-based techniques present the challenge of measuring these effects, while avoiding artifacts caused by the measurement technique itself. We performed a molecular dynamics study to investigate the mechanical properties of a GaN step of only a few lattice constants step height and scrutinized its applicability to indentation experiments using a finite element approach (FEM). We show that the breakdown of half-space symmetry leads to an "artificial" reduction of the elastic properties of comparable lateral dimensions which overlays the effect of surface stress. Contact resonance atomic force microscopy (CR-AFM) was used to compare the simulation results with experiments.
authors.affiliation: Leibniz-Institut für Oberflächenmodifizierung e.V. (IOM), Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Buchwald
authors.affiliation: Leibniz-Institut für Oberflächenmodifizierung e.V. (IOM), Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Sarmanova
authors.affiliation: Leibniz-Institut für Oberflächenmodifizierung e.V. (IOM), Permoserstr. 15, 04318 Leipzig, Germany ; Fakultät für Physik und Geowissenschaften, Universität Leipzig, 04103 Leipzig, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Rauschenbach
authors.affiliation: Leibniz-Institut für Oberflächenmodifizierung e.V. (IOM), Permoserstr. 15, 04318 Leipzig, Germany ; Fakultät für Physik und Geowissenschaften, Universität Leipzig, 04103 Leipzig, Germany ; Translationszentrum für regenerative Medizin (TRM), Universität Leipzig, 04103 Leipzig, Germany.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Mayr
keywords: finite elements; gallium nitride; indentation; mechanical properties; molecular dynamics; nanostructures