Regensburg 2010 – scientific programme
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DS: Fachverband Dünne Schichten
DS 47: [O] Plasmonics and Nanooptics VII (Joint Session DS/O/HL)
DS 47.3: Talk
Friday, March 26, 2010, 11:45–12:00, H32
Dynamical response of split-ring molecules for metamaterials — •Stephan Bernadotte1,2,3, Wim Klopper1,2, and Ferdinand Evers1,3 — 1Institut für Nanotechnologie, Karlsruher Institut für Technologie — 2Lehrstuhl für Theoretische Chemie, Institut für Physikalische Chemie, Karlsruher Institut für Technologie — 3Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie
We investigate the dynamical properties of molecular crystals (matrices) built up from nanometer sized ring shaped, conjugated molecules, which are candidate systems for negative index materials with frequencies in the optical regime. The response properties of such materials near their dynamical resonances can be understood in terms of an LRC circuit. In the conventional modeling of metamaterials, the circuit parameters enter (essentially) as phenomenological quantities. By contrast, in the present work they will be calculated from a microscopic tight binding model of a molecular Hamiltonian employing the Kubo approach.
We find that the LRC resonances of the molecular structures correspond to plasmonic excitations. By comparing to an analytical calculation, we can study in which way the plasmon resonances (and residues) depend on the molecule's electronic structure. On a qualitative level, our study also includes an investigation of the sensitivity of the dynamical response to the damping of the plasmons. Finally, we analyze the impact of cross-talk among the molecules within the matrix and the importance of birefringence terms.