Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 90: Poster III
HL 90.40: Poster
Donnerstag, 10. März 2016, 16:00–19:00, Poster A
Mechanical and vibrational properties of strained carbon nano-materials — •Alexander Croy1, Christian Wagner2, and Jörg Schuster3 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Center for Microtechnologies, TU Chemnitz, Germany — 3Fraunhofer Institute ENAS, Chemnitz, Germany
The introduction of carbon nanomaterials, like carbon nanotubes and graphene, into modern nano-electronic architectures is a wide field of application-oriented research — and requires reliable, non-destructive and fast characterization techniques to quantify defects and (local) strain. Optical spectroscopy, such as Raman spectroscopy, to indirectly probe phonons (vibrations), play a major role in this field.
Thus, a detailed understanding of the influence of defects and strain on Raman spectra is required, but the full ab-initio description of the coupled optical and phonon interaction is usually not feasible. Therefore, the problem is restricted to the main contribution by phonons — which are typically calculated by means of molecular dynamics (MD).
To maintain ab-initio accuracy, we compare the elastic properties of ideal and defective carbon nanostructures obtained by density functional calculations and different carbon force-fields. Within (static) numerical stretching experiments, we focus in particular on nonlinear contributions in the stress-strain-relation. Using MD calculations we study the strain- and defect dependence of the dominant phonon modes, i.e., their frequencies and life-times. Finally, we discuss consequences for Raman spectra.