Interplay between interference and Coulomb interaction in the ferromagnetic Anderson model with applied magnetic field
Pedersen, Jonas; Bohr, Dan; Wacker, Andreas; Novotny, Tomas, et al. (2009). Interplay between interference and Coulomb interaction in the ferromagnetic Anderson model with applied magnetic field. Physical Review B, 79,
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Published
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English
Authors:
Pedersen, Jonas
;
Bohr, Dan
;
Wacker, Andreas
;
Novotny, Tomas
, et al.
Department:
Mathematical Physics
Linne Center for Nanoscience and Quantum Engineering-lup-obsolete
Research Group:
Linne Center for Nanoscience and Quantum Engineering-lup-obsolete
Abstract:
We study the competition between interference due to multiple single-particle paths and Coulomb interaction in a simple model of an Anderson-type 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 found 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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