Kolloquium der Theoretischen Physik

From Institute for Theoretical Physics II / University of Erlangen-Nuremberg

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approximately every second Tuesday from 16:15 to 17:15 in Lecture Hall F

  • 13.06.2017 Ferdinand Evers (Uni Regensburg) Correlation effects in disordered and molecular quantum wires

In the absence of interactions between the charge carriers, metallic quantum wires do not exist due to the phenomenon of Anderson localization irrespective of the carrier temperature. With the discovery of many-body localization (MBL) we have learned that the wire remains insulating even in the presence of interactions, unless the interaction strength exceeds a critical threshold. The first part of the talk will present a brief overview about the phenomenology of MBL with an emphasis on recent discoveries concerning the long-time dynamics that remain to be understood. The second part of the presentation is devoted to molecular wires in the oligoacene family, i.e. benzene, naphthalene, antracene etc.. Calculations based on the density-functional theory (DFT) predict a lowest excitation gap that is an oscillating function of the wire length. Unlike it is the case for graphene nano-ribbons, the oscillation period is not fixed by the molecular geometry and therefore can be extremely large, of the order of 10 rings and more. As we verify by DMRG-calculations, the basic predictions of DFT remain valid even in the presence of strong (1D-typical) quantum fluctuations that are not included in available DFT functionals.