Kang Baolei, Liu Zhao, Zhao Dan, Zheng Lixuan, Sun Zeliang, Li Jian, Wang Zhengfei, Wu Tao, Chen Xianhui
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai, 200050, China.
Adv Mater. 2022 Jul;34(29):e2201597. doi: 10.1002/adma.202201597. Epub 2022 Jun 11.
The large negative magnetoresistance (MR) effect, which usually emerges in various magnetic systems, is a technologically important property for spintronics. Recently, the so-called "chiral anomaly" in topological semimetals offers an alternative to generate a considerable negative MR effect without utilizing magnetism. However, it requires that the applied magnetic field must be strictly along the electric current direction, which sets a strong limit for practical applications. Here, a giant negative MR effect is discovered with a value of up to -40% in 9 T at 2 K in the nonmagnetic Dirac material YCuAs , which is not restricted to the specific configuration for applied magnetic fields. Based on magnetic susceptibility and NMR measurements, the giant negative MR effect is tightly connected with the unexpected spin-dependent scattering from vacancy-induced local moments, which is also beyond the classical Kondo effect. The present work not only offers an alternative route for spintronics based on nonmagnetic topological materials, but also helps to further understand the negative MR effect in topological materials.
通常出现在各种磁系统中的大负磁阻（MR）效应，是自旋电子学中一项具有重要技术意义的特性。最近，拓扑半金属中所谓的“手征反常”为在不利用磁性的情况下产生可观的负磁阻效应提供了一种替代方法。然而，这要求所施加的磁场必须严格沿电流方向，这对实际应用设置了很大限制。在此，在非磁性狄拉克材料YCuAs中发现了巨大的负磁阻效应，在2 K温度下9 T磁场中其值高达 -40%，且不受所施加磁场特定配置的限制。基于磁化率和核磁共振测量，巨大的负磁阻效应与由空位诱导的局域磁矩产生的意外自旋相关散射紧密相关，这也超出了经典的近藤效应。本工作不仅为基于非磁性拓扑材料的自旋电子学提供了一条替代途径，还有助于进一步理解拓扑材料中的负磁阻效应。
