Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 2 (jointly with DY)

TT 19.3: Vortrag

Montag, 16. März 2015, 15:30–15:45, H 3010

Wannier-Stark Resonances in the current characteristics of an one-dimensional tight-binding chain and graphene nanoribbons: The role of interactions and dissipation — •Jakob Neumayer, Enirco Arrigoni, and Wolfgang von der Linden — Institut für Theoretische Physik - Computational Physics, Technische Universität Graz, Österreich

Electronic transport investigations of an infinite one-dimensional tight-binding chain and infinitely long graphene nanoribbons are performed within the Wannier-Stark model, where a homogeneous electric field is applied along the overall structure to drive a current to flow. Dissipation is represented in a simplified way by coupled voltage probes (artificial fermion bath chains) instead of an explicit consideration of phonons, to prevent an occurrence of Bloch Oscillations within the infinite geometries. Cluster Perturbation Theory is used to allow for an effective inclusion of electron correlations into the considered model.

Appearing Wannier-Stark resonances in the steady-state current characteristics of the correlated one-dimensional chain and graphene nanoribbons demand for a comprehensive understanding of the physical transport processes within the Wannier-Stark model, which is gained by an investigation of the physical system in terms of occurring resonant tunnelling processes. A non-interacting one-dimensional model system with alternating on-site energies is presented in conclusion, reproducing the current characteristics of the correlated tight-binding chain and allowing for a thorough explanation of the found oscillatory current behaviour.