论文标题
Quasi-Two-two分层抗FiferRomagnet Co $ _ {1/3} $ nbs $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $
Giant anomalous Hall effect in quasi-two-dimensional layered antiferromagnet Co$_{1/3}$NbS$_2$
论文作者
论文摘要
在散装金属反铁磁铁（AFMS）中发现异常的霍尔效应（AHE）激发了在二维（2D）系统中搜索相同现象的搜索，原则上可以观察到量化的异常霍尔电导。 Here, we present experiments on micro-fabricated devices based on Co$_{1/3}$NbS$_2$, a layered AFM that was recently found to exhibit AHE in bulk crystals below the Néel temperature T$_N$ = 29 K. Transport measurements reveal a pronounced resistivity anisotropy, indicating that upon lowering temperature the electronic coupling between individual atomic layers is increasingly suppressed.该实验还显示出非常大的异常霍尔电导率，约为400 s/cm，比散装大于一个数量级以上，这证明了在小型去角质晶体中研究AHE的重要性，受到晶体缺陷的影响较小。有趣的是，当对应的异常大厅电导归一化为原子飞机的数量时，为$ \ sim \，0.6 \; E^2/h $每层接近量化异常效果的预期值。观察到的强烈的运输各向异性和每层非常大的异常大厅电导使Co $ _ {1/3} $ nbs $ _2 $的特性与存在源自抗毒素磁性状态的磁性超结构的部分非平底2D频带兼容。因此，将该材料的原子薄层隔离并控制其电荷密度可能会提供可行的途径，以揭示2D AFM中量化AHE的发生。
The discovery of the anomalous Hall effect (AHE) in bulk metallic antiferromagnets (AFMs) motivates the search of the same phenomenon in two-dimensional (2D) systems, where a quantized anomalous Hall conductance can in principle be observed. Here, we present experiments on micro-fabricated devices based on Co$_{1/3}$NbS$_2$, a layered AFM that was recently found to exhibit AHE in bulk crystals below the Néel temperature T$_N$ = 29 K. Transport measurements reveal a pronounced resistivity anisotropy, indicating that upon lowering temperature the electronic coupling between individual atomic layers is increasingly suppressed. The experiments also show an extremely large anomalous Hall conductivity of approximately 400 S/cm, more than one order of magnitude larger than in the bulk, which demonstrates the importance of studying the AHE in small exfoliated crystals, less affected by crystalline defects. Interestingly, the corresponding anomalous Hall conductance, when normalized to the number of contributing atomic planes, is $\sim \, 0.6 \; e^2/h$ per layer, approaching the value expected for the quantized anomalous Hall effect. The observed strong anisotropy of transport and the very large anomalous Hall conductance per layer make the properties of Co$_{1/3}$NbS$_2$ compatible with the presence of partially filled topologically non-trivial 2D bands originating from the magnetic superstructure of the antiferromagnetic state. Isolating atomically thin layers of this material and controlling their charge density may therefore provide a viable route to reveal the occurrence of the quantized AHE in a 2D AFM.
