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Ferromagnetism of Weakly-Interacting Electrons in Disordered Systems

Xiao Yang·Chetan Nayak
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Abstract

It was realized two decades ago that the two-dimensional diffusive Fermi liquid phase is unstable against arbitrarily weak electron-electron interactions. Recently, using the nonlinear sigma model developed by Finkelstein, several authors have shown that the instability leads to a ferromagnetic state. In this paper, we consider diffusing electrons interacting through a ferromagnetic exchange interaction. Using the Hartree-Fock approximation to directly calculate the electron self energy, we find that the total energy is minimized by a finite ferromagnetic moment for arbitrarily weak interactions in two dimensions and for interaction strengths exceeding a critical proportional to the conductivity in three dimensions. We discuss the relation between our results and previous ones.

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Xiao Yang, Chetan Nayak. 2005-01-18. Ferromagnetism of Weakly-Interacting Electrons in Disordered Systems. https://doi.org/10.1103/physrevb.72.052405

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