Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA.
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA.
Nat Mater. 2017 Jan;16(1):94-100. doi: 10.1038/nmat4783. Epub 2016 Oct 31.
Magnetic topological insulators such as Cr-doped (Bi,Sb)Te provide a platform for the realization of versatile time-reversal symmetry-breaking physics. By constructing heterostructures exhibiting Néel order in an antiferromagnetic CrSb and ferromagnetic order in Cr-doped (Bi,Sb)Te, we realize emergent interfacial magnetic phenomena which can be tailored through artificial structural engineering. Through deliberate geometrical design of heterostructures and superlattices, we demonstrate the use of antiferromagnetic exchange coupling in manipulating the magnetic properties of magnetic topological insulators. Proximity effects are shown to induce an interfacial spin texture modulation and establish an effective long-range exchange coupling mediated by antiferromagnetism, which significantly enhances the magnetic ordering temperature in the superlattice. This work provides a new framework on integrating topological insulators with antiferromagnetic materials and unveils new avenues towards dissipationless topological antiferromagnetic spintronics.
磁性拓扑绝缘体，如 Cr 掺杂（Bi，Sb）Te，为实现多功能时间反转对称性破缺物理提供了平台。通过构建在反铁磁 CrSb 中表现出奈尔有序、在 Cr 掺杂（Bi，Sb）Te 中表现出铁磁有序的异质结构，我们实现了新兴的界面磁性现象，这些现象可以通过人工结构工程进行调整。通过对异质结构和超晶格的精心几何设计，我们证明了利用反铁磁交换耦合来控制磁性拓扑绝缘体的磁性性质。研究表明，近邻效应会诱导界面自旋织构调制，并通过反铁磁作用建立有效的长程交换耦合，从而显著提高超晶格中的磁有序温度。这项工作为将拓扑绝缘体与反铁磁材料集成提供了一个新的框架，并为无损耗拓扑反铁磁自旋电子学开辟了新途径。
