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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Molecular Electronics and Excited State Properties II
CPP 20.1: Vortrag
Montag, 16. März 2020, 15:00–15:15, ZEU 260
Modeling the Complex Band Structure of Conjugated Polymers via Kronig-Penney-like Models — •Florian Günther1, Kevin Preis2, and Sibylle Gemming2,3 — 1Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil — 2Institut für Physik, Technische Universität Chemnitz, Chemnitz, Germany — 3Institut für Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
In molecular electronics, it is crucial to understand and control the electronic properties of the involved materials. Due to the small length scale, which is in the range of nanometers and below, the coherent electron tunneling plays an important role in the conduction behavior of the used compounds. Its exponential decay with the length can be studied by considering the complex band structure in the region of the Fermi energy.
In our work, we calculate the real and the complex bands of various conjugated polymers using the density functional based tight binding approach. The results are fitted with the analytical solutions arising from the two-band tight binding and the Kronig-Penney models. While the former exhibits less free parameters, the latter is able to reproduce the non-symmetric shape of the complex bands with respect to the Fermi energy. We found that the product of the barrier height and width of the Kronig-Penney model correlates with the tunneling inverse decay length. Our results suggest that the coherent electron tunneling through conjugated polymers can be estimated by fitting the Kronig-Penney model to the real band structure.