A high-temperature ferromagnetic topological insulating phase by proximity coupling
A high-temperature ferromagnetic topological insulating phase by proximity coupling
复制标题
DOI：
10.1038/nature17635
复制
发表时间：
2016-05-26
期刊：
影响因子：
64.8
通讯作者：
Moodera, Jagadeesh S.
中科院分区：
文献类型：
--
作者：
Katmis, Ferhat;Lauter, Valeria;Moodera, Jagadeesh S.
拓扑绝缘体是显示受时间反转对称性（1，）2保护的导电表面状态的绝缘材料，其中电子自旋被锁定到它们的动量。这种独特的性质为创造下一代电子，自旋电子和量子计算设备开辟了新的机会（3-5）。在拓扑绝缘体系统中引入铁磁有序而不损害其独特的量子相干特征，可能会导致实现几种预测的物理现象（6，7）。特别是，在特定位置的拓扑绝缘体表面实现强大的长程磁序，而不引入自旋散射中心，可以为器件开辟新的可能性。在这里，我们使用自旋极化中子反射率实验来证明拓扑增强界面磁性耦合铁磁绝缘体（EuS）的拓扑绝缘体（Bi 2Se 3）在双层系统。这种界面铁磁性持续到室温，即使铁磁性绝缘体已知仅在低温下有序铁磁性（
Topological insulators are insulating materials that display conducting surface states protected by time-reversal symmetry(1,)2, wherein electron spins are locked to their momentum. This unique property opens up new opportunities for creating next-generation electronic, spintronic and quantum computation devices(3-5). Introducing ferromagnetic order into a topological insulator system without compromising its distinctive quantum coherent features could lead to the realization of several predicted physical phenomena(6,7). In particular, achieving robust long-range magnetic order at the surface of the topological insulator at specific locations without introducing spin-scattering centres could open up new possibilities for devices. Here we use spin-polarized neutron reflectivity experiments to demonstrate topologically enhanced interface magnetism by coupling a ferromagnetic insulator (EuS) to a topological insulator (Bi2Se3) in a bilayer system. This interfacial ferromagnetism persists up to room temperature, even though the ferromagnetic insulator is known to order ferromagnetically only at low temperatures (