论文标题
拓扑抗铁磁状态的电气操作
Electrical Manipulation of a Topological Antiferromagnetic State
论文作者
论文摘要
由于非平凡带拓扑而引起的新兴现象的电气操纵是使用拓扑保护实现下一代技术的关键。 Weyl Semimetal是一个三维无间隙系统，该系统将Weyl Fermions作为低能量准颗粒。它表现出各种外来现象，例如大型异常效应（AHE）和手性异常，它们由于受拓扑保护的Weyl节点而具有强大的特性。为了操纵这种现象，Weyl Semimetals的磁性版本将是有用的，因为磁纹理可能会提供一个手柄，用于控制Brillouin区域中的Weyl节点的位置。此外，鉴于抗铁磁（AF）旋转的前景用于实现具有超快操作的高密度设备，如果可以电气操纵AF Weyl Metal，那将是理想的选择。但是，尚无关于Weyl金属的电气操作的报告。在这里，我们证明了拓扑AF状态的电气切换及其在室温下AHE检测。特别是，我们采用了AF Weyl Metal Mn $ _3 $ sn的多晶薄膜，该薄膜表现为零场AHE。 Using the bilayer device of Mn$_3$Sn and nonmagnetic metals (NMs), we find that an electrical current density of $\sim 10^{10}$-$10^{11}$ A/m$^2$ in NMs induces the magnetic switching with a large change in Hall voltage, and besides, the current polarity along a bias field and the sign of the spin Hall angle $θ_ {\ rm sh} $ of NMS [pt（$θ_{\ rm sh}> 0 $），cu（$θ_ {\ rm sh} \ sim 0 $），w（$θ_{$θ_ {\ rm sh} <0 $）]确定厅的符号。值得注意的是，使用与铁磁金属使用的方案相同的方案制成了抗铁磁铁中的电交换。我们的观察可能会导致拓扑磁性和AF Spintronics的科学技术飞跃。
Electrical manipulation of emergent phenomena due to nontrivial band topology is a key to realize next-generation technology using topological protection. A Weyl semimetal is a three-dimensional gapless system that hosts Weyl fermions as low-energy quasiparticles. It exhibits various exotic phenomena such as large anomalous Hall effect (AHE) and chiral anomaly, which have robust properties due to the topologically protected Weyl nodes. To manipulate such phenomena, the magnetic version of Weyl semimetals would be useful as a magnetic texture may provide a handle for controlling the locations of Weyl nodes in the Brillouin zone. Moreover, given the prospects of antiferromagnetic (AF) spintronics for realizing high-density devices with ultrafast operation, it would be ideal if one could electrically manipulate an AF Weyl metal. However, no report has appeared on the electrical manipulation of a Weyl metal. Here we demonstrate the electrical switching of a topological AF state and its detection by AHE at room temperature. In particular, we employ a polycrystalline thin film of the AF Weyl metal Mn$_3$Sn, which exhibits zero-field AHE. Using the bilayer device of Mn$_3$Sn and nonmagnetic metals (NMs), we find that an electrical current density of $\sim 10^{10}$-$10^{11}$ A/m$^2$ in NMs induces the magnetic switching with a large change in Hall voltage, and besides, the current polarity along a bias field and the sign of the spin Hall angle $θ_{\rm SH}$ of NMs [Pt ($θ_{\rm SH} > 0$), Cu($θ_{\rm SH} \sim 0$), W ($θ_{\rm SH} < 0$)] determines the sign of the Hall voltage. Notably, the electrical switching in the antiferromagnet is made using the same protocol as the one used for ferromagnetic metals. Our observation may well lead to another leap in science and technology for topological magnetism and AF spintronics.
