Competing ferromagnetic and charge-ordered states in models for manganites: The origin of the colossal magnetoresistance effect
Competing ferromagnetic and charge-ordered states in models for manganites: The origin of the colossal magnetoresistance effect
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DOI：
10.1103/physrevlett.98.127202
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发表时间：
2007-03-23
影响因子：
8.6
通讯作者：
Dagotto, Elbio
中科院分区：
文献类型：
--
作者：
Sen, Cengiz;Alvarez, Gonzalo;Dagotto, Elbio
采用大规模Monte Carlo方法研究了具有超交换耦合J（AF）和合作声子的锰氧化物单轨道模型。两个轨道的结果也进行了简要的讨论。专注于电子密度n=0.75，铁磁金属和电荷有序（CO）绝缘状态之间的竞争制度被确定。在相关的双临界点附近，观察到庞磁电阻（CMR）效应。CMR与极化子之间的短程相关性的发展有关，高于自旋有序温度，类似于低温CO状态的电荷排列。
The one-orbital model for manganites with cooperative phonons and superexchange coupling J(AF) is investigated via large-scale Monte Carlo simulations. The results for two orbitals are also briefly discussed. Focusing on the electron density n=0.75, a regime of competition between ferromagnetic metallic and charge-ordered (CO) insulating states is identified. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects are 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.