Fu Yu, Huang Yu, He Qing Lin
International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China.
Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China.
Nat Commun. 2025 Mar 29;16(1):3058. doi: 10.1038/s41467-025-58401-5.
Coulomb interaction between two closely spaced but electrically isolated conductors can induce a voltage in one of them upon feeding a current into the other. This effect has been widely studied in nonmagnetic strongly interacting systems and historically interpreted in terms of momentum and energy exchanges, which thus complies with Onsager's reciprocity. Here we report the non-reciprocal Coulomb drag observed between two ferromagnetic Chern insulators that host quantum anomalous Hall effects. By measurements with current and circuit reversals, we discovered strong drag signals in both the longitudinal and transverse directions which violate Onsager's reciprocity. These drag signals only emerge when the Chern insulator is in a multidomain state. Combined with the nonlinear characteristics and power-law temperature dependence, this drag is attributed to the rectifications of mesoscopic fluctuations and quantum shot noise as well as the current cumulant. The drag signals are accompanied by strong magnetic fluctuations, highlighting the role played by magnetic dynamics. The present study expands the Coulomb drag to the realm of magnetic topological systems.
当向两个靠得很近但电绝缘的导体中的一个通入电流时，它们之间的库仑相互作用会在另一个导体中感应出电压。这种效应在非磁性强相互作用系统中已得到广泛研究，并且历史上是根据动量和能量交换来解释的，因此符合昂萨格互易性。在此，我们报告了在两个呈现量子反常霍尔效应的铁磁陈绝缘体之间观察到的非互易库仑拖拽。通过对电流和电路进行反转测量，我们发现在纵向和横向都存在强烈的拖拽信号，这违反了昂萨格互易性。这些拖拽信号仅在陈绝缘体处于多畴状态时出现。结合非线性特性和幂律温度依赖性，这种拖拽归因于介观涨落和量子散粒噪声的整流以及电流累积量。拖拽信号伴随着强烈的磁涨落，突出了磁动力学所起的作用。本研究将库仑拖拽扩展到了磁拓扑系统领域。
