Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.73: Poster

Wednesday, March 28, 2007, 14:00–17:45, Poster A

Density functional theory for spinless fermions in one dimension — •Stefan Schenk, Peter Schwab, and Ulrich Eckern — Universität Augsburg

Density functional theory (DFT) within the local density approximation is well known to provide a realistic description of the electronic structure of numerous complex materials, including surfaces and interfaces.

Useful insights into the limitations of DFT can be obtained by considering simple lattice models [1]. In this context, we investigate a one-dimensional model of spinless fermions. An advantage of this model is that the exact exchange-correlation energy of the homogeneous system can be obtained by use of the Bethe-Ansatz. Starting from this exact calculation we employ two methods, the local density approximation and an approximation which includes the exact exchange energy. We compare with results obtained by exact diagonalisation of small systems.

In a next step we include magnetic fields. Therefore we extend the DFT to current density functional theory on a lattice. As in the previous case we investigate the accuracy of our methods by comparison with exact results.

[1] K. Schönhammer, O. Gunnarsson, and R. M. Noack, Phys. Rev. B 52, 2504 (1995)