Sen Cengiz, Alvarez Gonzalo, Dagotto Elbio
National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, Florida 32310, USA.
Phys Rev Lett. 2007 Mar 23;98(12):127202. doi: 10.1103/PhysRevLett.98.127202. Epub 2007 Mar 21.
The one-orbital model for manganites with cooperative phonons and superexchange coupling JAF 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.
通过大规模蒙特卡罗模拟研究了具有协同声子和超交换耦合JAF的锰氧化物的单轨道模型。还简要讨论了双轨道的结果。聚焦于电子密度n = 0.75，确定了铁磁金属态和电荷有序（CO）绝缘态之间的竞争区域。在相关双临界点附近，观察到巨磁电阻（CMR）效应。CMR与高于自旋有序温度时极化子之间短程关联的发展有关，类似于低温CO态的电荷排列。
