Magnetic Polarons in the 1D FM Kondo Model

Winfried Koller, Alexander Prüll, Hans Gerd Evertz, Wolfgang von der Linden

Research output: Contribution to journalArticleResearchpeer-review

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(\omega) 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.
Original languageUndefined/Unknown
JournalPhysical Review / B
DOIs
Publication statusPublished - 20 Jan 2003

Keywords

  • cond-mat.str-el

Cite this

Magnetic Polarons in the 1D FM Kondo Model. / Koller, Winfried; Prüll, Alexander; Evertz, Hans Gerd; Linden, Wolfgang von der.

In: Physical Review / B, 20.01.2003.

Research output: Contribution to journalArticleResearchpeer-review

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AB - 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(\omega) 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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