Spin-orbit-driven magnetic structure and excitation in the 5d pyrochlore Cd2Os2O7.
Spin-orbit-driven magnetic structure and excitation in the 5d pyrochlore Cd2Os2O7.
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DOI：
10.1038/ncomms11651
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发表时间：
2016-06-07
影响因子：
16.6
通讯作者：
Christianson AD
中科院分区：
文献类型：
--
作者：
Calder S;Vale JG;Bogdanov NA;Liu X;Donnerer C;Upton MH;Casa D;Said AH;Lumsden MD;Zhao Z;Yan JQ;Mandrus D;Nishimoto S;van den Brink J;Hill JP;McMorrow DF;Christianson AD
自旋-轨道耦合（SOC）在5d氧化物中的作用，特别是在新电子态的形成和金属-绝缘体转变（MITs）方面的作用，已经引起了人们的广泛关注。SOC起着主导作用，在5d 5虹彩（Ir 4+），经历MIT的并发（pyrophormites）和分离（钙钛矿）从发病的磁性秩序。然而，SOC对于其他5d配置的作用不太清楚。例如，5d3（Os 5+）系统预计将有一个减少有效SOC的轨道单线态。然而，烧绿石Cd 2 Os 2 O 7表现出MIT englance与磁序现象学上类似的烧绿石铱酸盐。在这里，我们解决了磁结构的Cd 2 Os 2 O 7与中子衍射，然后通过共振非弹性X射线散射确定显着的电子和磁性的能量尺度控制MIT。特别是，SOC在创建电子基态中起着微妙的作用，但驱动磁秩序和出现多自旋翻转磁激发。 在5d材料如锇酸盐中，强的电子相关性可以与自旋轨道耦合联合收割机结合，产生新的有序。在这里，作者演示了如何在烧绿石Cd 2 Os 2 O 7自旋轨道耦合产生磁秩序和激发与磁性金属-绝缘体过渡。
Much consideration has been given to the role of spin-orbit coupling (SOC) in 5d oxides, particularly on the formation of novel electronic states and manifested metal-insulator transitions (MITs). SOC plays a dominant role in 5d5 iridates (Ir4+), undergoing MITs both concurrent (pyrochlores) and separated (perovskites) from the onset of magnetic order. However, the role of SOC for other 5d configurations is less clear. For example, 5d3 (Os5+) systems are expected to have an orbital singlet with reduced effective SOC. The pyrochlore Cd2Os2O7 nonetheless exhibits a MIT entwined with magnetic order phenomenologically similar to pyrochlore iridates. Here, we resolve the magnetic structure in Cd2Os2O7 with neutron diffraction and then via resonant inelastic X-ray scattering determine the salient electronic and magnetic energy scales controlling the MIT. In particular, SOC plays a subtle role in creating the electronic ground state but drives the magnetic order and emergence of a multiple spin-flip magnetic excitation. Strong electronic correlations in 5d materials such as osmates may combine with spin-orbit coupling to yield novel order. Here, the authors demonstrate how spin-orbit coupling in pyrochlore Cd2Os2O7 generates magnetic order and excitations associated with a magnetic metal-insulator transition.