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arXiv · 0810.5293

Interplay between interference and Coulomb interaction in the ferromagnetic Anderson model with applied magnetic field

Jonas Nyvold Pedersen·Dan Bohr·Andreas Wacker·Tomas Novotny·Peter Schmitteckert·Karsten Flensberg
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Abstract

We study the competition between interference due to multiple single-particle paths and Coulomb interaction in a simple model of an Anderson-like impurity with local-magnetic-field-induced level splitting coupled to ferromagnetic leads. The model along with its potential experimental relevance in the field of spintronics serves as a nontrivial benchmark system where various quantum transport approaches can be tested and compared. We present results for the linear conductance obtained by a spin-dependent implementation of the density matrix renormalization group scheme which are compared with a mean-field solution as well as a seemingly more advanced Hubbard-I approximation. We explain why mean-field yields nearly perfect results, while the more sophisticated Hubbard-I approach fails, even at a purely conceptual level since it breaks hermiticity of the related density matrix. Furthermore, we study finite bias transport through the impurity by the mean-field approach and recently developed higher-order density matrix equations. We find that the mean-field solution fails to describe the plausible results of the higher-order density matrix approach both quantitatively and qualitatively as it does not capture some essential features of the current-voltage characteristics such as negative differential conductance.

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Jonas Nyvold Pedersen, Dan Bohr, Andreas Wacker, Tomas Novotny, Peter Schmitteckert, Karsten Flensberg. 2008-10-29. Interplay between interference and Coulomb interaction in the ferromagnetic Anderson model with applied magnetic field. https://doi.org/10.1103/physrevb.79.125403

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