AI 中文总结
本研究针对Ru/[Co/Ni]$_N$多层膜，发现通过控制Ru层堆叠顺序可实现反常霍尔效应的符号反转，明确该效应源于Ru底层施加的面内拉伸应变，为调控贝里曲率驱动的输运提供了新方法。
AI 中文摘要
反常霍尔效应（Anomalous Hall effect, AHE）是铁磁体中由相对论自旋-轨道相互作用产生的标志性输运现象。本研究报道了Ru/[Co/Ni]$_N$多层膜中AHE的意外符号反转，该现象由Ru层的堆叠顺序控制：当Ru置于Co/Ni多层膜下方而非上方时，反常霍尔信号从正转为负。通过系统改变多层膜重复次数N，并结合输运测量与第一性原理计算，研究表明该反转源于Ru底层施加的面内拉伸应变，该应变会重构电子结构并重新分配费米能级附近的贝里曲率。本研究结果确立了界面应变作为调控贝里曲率驱动输运的有效旋钮，并为磁性多层膜中应变控制的拓扑输运现象提供了途径。
英文摘要
The anomalous Hall effect (AHE) is a hallmark transport phenomenon in ferromagnets arising from relativistic spin-orbit interaction. Here, we report an unexpected sign reversal of the AHE in Ru/[Co/Ni]$_N$ multilayers controlled by the stacking sequence of the Ru layer. When Ru is placed beneath, rather than atop, the Co/Ni multilayers, the anomalous Hall signal switches from positive to negative. By systematically varying the multilayer repeat number N and combining transport measurements with first-principles calculations, we show that this reversal originates from in-plane tensile strain imposed by the Ru underlayer, which reshapes the electronic structure and redistributes Berry curvature near the Fermi level. Our findings establish interfacial strain as an effective knob for tuning Berry-curvature-driven transport and suggest a pathway toward strain-controlled topological transport phenomena in magnetic multilayers.
