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Portrait of Andreas Wacker. Photo: Kennet Ruona

Andreas Wacker


Portrait of Andreas Wacker. Photo: Kennet Ruona

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


  • Jonas Pedersen
  • Dan Bohr
  • Andreas Wacker
  • Tomas Novotny
  • Peter Schmitteckert
  • Karsten Flensberg

Summary, in English

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.


  • Mathematical Physics

Publishing year





Physical Review B



Document type

Journal article


American Physical Society


  • Condensed Matter Physics



Research group

  • Linne Center for Nanoscience and Quantum Engineering


  • ISSN: 1550-235X