Competing Ferromagnetic and Charge-Ordered States in Models for Manganites: the Origin of the CMR Effect
Abstract
The one-orbital model for manganites with cooperative phonons and superexchange coupling $J_{\rm AF}$ has been investigated via large-scale Monte Carlo (MC) simulations. Results for two-orbitals are also briefly discussed. Focusing on electronic density $n$=0.75, a regime of competition between ferromagnetic (FM) metallic and charge-ordered (CO) insulating states was identified. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects were observed. The CMR is associated with the development of short-distance correlations among polarons, above the spin ordering temperatures, resembling the charge arrangement of the low-temperature CO state.
- Publication:
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arXiv e-prints
- Pub Date:
- February 2007
- DOI:
- arXiv:
- arXiv:cond-mat/0702426
- Bibcode:
- 2007cond.mat..2426S
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Materials Science
- E-Print:
- 4 pages, 4 figures, accepted for publication in the Phys. Rev. Lett