Non-reciprocal Coulomb drag between Chern insulators

作者：Yu Fu, Yu Huang, Qinglin He · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-58401-5 · 被引用次数：6 · 研究领域：Topological Materials and Phenomena、Atomic and Subatomic Physics Research、Advanced Condensed Matter Physics

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 $$I-V$$ 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. An applied current in one conductor can induce a voltage in another closely spaced conductor through Coulomb interactions. Here, the authors expand this effect to magnetic topological systems, by revealing Coulomb drag signals violating Onsager’s reciprocity in the Chern insulator in a multidomain state.