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Magnetic Polarons in the 1D FM Kondo Model

Winfried Koller·Alexander Prüll·Hans Gerd Evertz·Wolfgang von der Linden
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Abstract

The ferromagnetic Kondo model with classical corespins is studied via unbiased Monte-Carlo simulations. We show that with realistic parameters for the manganites and at low temperatures, the double-exchange mechanism does not lead to phase separation in one-dimensional chains but rather stabilizes individual ferromagnetic polarons. Within the ferromagnetic polaron picture, the pseudogap in the one-particle spectral function A_k(ω) can easily be explained. Ferromagnetic polarons also clear up a seeming failure of the double-exchange mechanism in explaining the comparable bandwidths in the ferromagnetic and paramagnetic phase. For our analysis, we extend a simplified model, the finite temperature uniform hopping approach (UHA), to include polarons. It can easily be evaluated numerically and provides a simple quantitative understanding of the physical features of the ferromagnetic Kondo model.

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Winfried Koller, Alexander Prüll, Hans Gerd Evertz, Wolfgang von der Linden. 2003-01-23. Magnetic Polarons in the 1D FM Kondo Model. https://doi.org/10.1103/physrevb.67.174418

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