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arXiv · 1207.1525

Double Exchange Ferromagnetism in the Peierls Insulator State

S. Nishimoto·Y. Ohta
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Abstract

We study the effects of opening of the band gap on the double exchange ferromagnetism. Applying the density-matrix renormalization group method and an analytical expansion from the dimer limit to the one-dimensional double exchange model, we demonstrate for a relevant region of the exchange coupling that, in the weak dimerization regime, the Peierls gap opens in the fully spin-polarized conduction band without affecting its ferromagnetism, whereas in the strong dimerization regime, the ferromagnetism is destroyed and the Mott gap opens instead, leading the system to the antiferromagnetic quasi-long-range order. An insulator version of the double exchange ferromagnetism is thus established.

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S. Nishimoto, Y. Ohta. 2012-07-06. Double Exchange Ferromagnetism in the Peierls Insulator State. https://doi.org/10.1103/physrevlett.109.076401

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