Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 7: Focus Session: Functional Molecules at Surfaces I
O 7.10: Talk
Monday, March 16, 2020, 13:00–13:15, TRE Ma
Tuning topological phase transition and pi-conjugation of 1D pentacene polymers by their length — •Héctor González-Herrero1, Bruno de la Torre1, Adam Matěj1, Shayan Edalatmanesh1, Nazario Martín2, David Écija2, and Pavel Jelínek1 — 1Regional Centre of Advanced Technologies and Materials. Palacký University, 78371 Olomouc, Czech Republic. — 2IMDEA Nanociencia.28049, Madrid, Spain.
The recent study of ethynylene-bridged polyacene polymers has shown the possibility to tune band gap by proximity of the topological phase transition [1]. In the specific case of pentacene polymers situated near the phase transition, a small bandgap of 350 meV and the appearance of edge-states have been reported. This behavior is attributed to a topological transition from trivial to non-trivial phases. However, minimum length required for a polymer to exhibit this transition is not clear.
Theoretical analysis based on total energy DFT simulations predicts that while dimer and trimer pentacene wire adopts aromatic pi-conjugation, longer wires exhibits quinoid ?-conjugation with presence of characteristic zero bias edge states. Motived by this observation, we have grown short pentacene chains in order to study the impact of their length in the final properties of the polymer. Using STM and AFM techniques we will characterize the electronic and structural properties trying to find the key parameters for the topological phase transition to take place and benchmark the theoretical prediction.
[1] B. Cirera et al arXiv:1911.04414.