Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 101: Transport - Poster Session

TT 101.14: Poster

Thursday, April 3, 2014, 15:00–19:00, P2

Effects of electronic correlations and magnetic field on a molecular ring out of equilibrium — •Martin Nuss, Enrico Arrigoni, and Wolfgang von der Linden — Institute of Theoretical and Computational Physics, Graz University of Technology

We study effects of electron-electron interactions on the steady-state characteristics of a hexagonal molecular ring in a magnetic field, as a model for a benzene molecular junction. The system is driven out of equilibrium by applying a bias voltage across two metallic leads. We employ a model Hamiltonian approach to evaluate the effects of on-site as well as nearest-neighbor density-density type interactions in a physically relevant parameter regime. Results for the steady-state current, charge density and magnetization in three different junction setups (para, meta and ortho) are presented. Our findings indicate that interactions beyond the mean-field level renormalize voltage thresholds as well as current plateaus. Electron-electron interactions lead to substantial charge redistribution as compared to the mean-field results. It is shown that electron-electron interactions do not qualitatively change the current-voltage characteristics in magnetic fields as compared to the noninteracting case in a charge-neutral setup. We identify a strong response of the circular current on the electronic structure of the metallic leads. Our results are obtained by steady-state Cluster Perturbation Theory, a systematically improvable approximation to study interacting molecular junctions out of equilibrium, even in magnetic fields. The method is flexible and fast and can straight-forwardly be applied to effective models as obtained from ab-initio calculations.