Phase competition in the double-exchange model on the frustrated pyrochlore lattice.
Phase competition in the double-exchange model on the frustrated pyrochlore lattice.
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DOI：
10.1103/physrevlett.104.106407
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发表时间：
2010-02
影响因子：
8.6
通讯作者：
Y. Motome;N. Furukawa
中科院分区：
文献类型：
--
作者：
Y. Motome;N. Furukawa
在几何阻挫存在的条件下，研究了铁磁双交换相互作用与超交换反铁磁相互作用之间的竞争。随着超交换相互作用的增加，铁磁金属变得不稳定，并被合作的顺磁金属所取代，这与在没有挫折的情况下向反铁磁绝缘体的不连续过渡形成鲜明对比。在临界区，系统表现出一个特殊的温度无关的行为与高度不相干的运输，表明在低温下的大的剩余熵。我们讨论了这些结果与钼烧绿石氧化物中压力诱导行为的相关性[S。Iguchi等人，物理修订信函102，136407（2009）]。
Competition between the ferromagnetic double-exchange interaction and the superexchange antiferromagnetic interaction is theoretically studied in the presence of geometrical frustration. As the superexchange interaction increases, the ferromagnetic metal becomes unstable and is taken over by a cooperative paramagnetic metal, in sharp contrast to a discontinuous transition to the antiferromagnetic insulator in the absence of frustration. In the critical region, the system exhibits a peculiar temperature-independent behavior with highly incoherent transport, suggesting a large residual entropy at low temperatures. We discuss the relevance of the results to the pressure-induced behaviors in Mo pyrochlore oxides [S. Iguchi et al., Phys. Rev. Lett. 102, 136407 (2009)].