Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 22: Transport: Poster Session

TT 22.27: Poster

Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B

Conductance through a strongly interacting region -- LDA versus exact results — •Stefan Schenk, Michael Dzierzawa, Ulrich Eckern, and Peter Schwab — Universität Augsburg

Density functional theory within the local density approximation is the method of choice for calculations of the electronic structure of complex materials. In recent years the method has been adapted to transport problems, in particular to transport through systems of molecular size.

Here we study a one-dimensional model of spinless fermions. This has the advantage that the density matrix renormalization group provides numerically exact results for the conductance. We find that although for weak electron-electron interaction the local density approximation gives reasonable estimates for the location of conductance resonances, the method strongly overestimates the conductance in the non-resonant case. The discrepancies arise from the insufficient accuracy of the ground state density obtained within the local density approximation. Dynamic effects that can be captured within the time-dependent density functional theory are only of minor importance.