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arXiv · 0712.0296

Failure of mean-field approach in out-of-equilibrium Anderson model

Bertalan Horváth·Bence Lazarovits·Olivier Sauret·Gergely Zaránd
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Abstract

To explore the limitations of the mean field approximation, frequently used in \textit{ab initio} molecular electronics calculations, we study an out-of-equilibrium Anderson impurity model in a scattering formalism. We find regions in the parameter space where both magnetic and non-magnetic solutions are stable. We also observe a hysteresis in the non-equilibrium magnetization and current as a function of the applied bias voltage. The mean field method also predicts incorrectly local moment formation for large biases and a spin polarized current, and unphysical kinks appear in various physical quantities. The mean field approximation thus fails in every region where it predicts local moment formation.

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Bertalan Horváth, Bence Lazarovits, Olivier Sauret, Gergely Zaránd. 2007-12-03. Failure of mean-field approach in out-of-equilibrium Anderson model. https://doi.org/10.1103/physrevb.77.113108

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