Effect of lattice geometry on magnon Hall effect in ferromagnetic insulators
Effect of lattice geometry on magnon Hall effect in ferromagnetic insulators
复制标题
DOI：
10.1103/physrevb.85.134411
复制
发表时间：
2012-04-04
影响因子：
3.7
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Ideue, T.;Onose, Y.;Tokura, Y.
我们研究了各种铁磁绝缘体中磁振子的热霍尔效应。对于烧绿石铁磁绝缘体Lu_2V_2O_7、Ho_2V_2O_7和In_2Mn_2O_7，在居里温度T-C以下观察到有限的霍尔热导率。从温度和磁场的依赖性，它的结论是，磁振子负责的热霍尔效应。基于Dzyaloshinskiii-Moriya（DM）相互作用在动量空间中诱导的Berry曲率的理论可以很好地解释磁振子的Hall效应。该分析已扩展到具有钙钛矿结构的过渡金属（TM）氧化物。La_2NiMnO_6和YTiO_3具有畸变的钙钛矿结构，晶胞中有四个TM离子，热霍尔信号不存在或小得多。另一方面，在另一种铁磁钙钛矿氧化物BiMnO 3中，在TC以下可以辨别有限的热霍尔响应，其显示具有较大晶胞的轨道有序。在绝缘烧绿石和钙钛矿体系中，热霍尔效应的存在与否反映了DM诱导磁振子霍尔效应的几何和拓扑方面。
We have investigated the thermal Hall effect of magnons for various ferromagnetic insulators. For pyrochlore ferromagnetic insulators Lu2V2O7, Ho2V2O7, and In2Mn2O7, finite thermal Hall conductivities have been observed below the Curie temperature T-C. From the temperature and magnetic-field dependencies, it is concluded that magnons are responsible for the thermal Hall effect. The Hall effect of magnons can be well explained by the theory based on the Berry curvature in momentum space induced by the Dzyaloshinskii-Moriya (DM) interaction. The analysis has been extended to the transition-metal (TM) oxides with perovskite structure. The thermal Hall signal was absent or far smaller in La2NiMnO6 and YTiO3, which have the distorted perovskite structure with four TM ions in the unit cell. On the other hand, a finite thermal Hall response is discernible below TC in another ferromagentic perovskite oxide BiMnO3, which shows orbital ordering with a larger unit cell. The presence or absence of the thermal Hall effect in insulating pyrochlore and perovskite systems reflect the geometric and topological aspect of DM-induced magnon Hall effect.