In 1861, Maxwell conceived the idea of the displacement current, which then made laws of electrodynamics more complete and also resulted in the realization of devices exploiting such displacement current. Interestingly, it is presently unknown if such displacement current can result in large intrinsic ac current in ferroic systems possessing domains, despite the flurry of recent activities that have been devoted to domains and their corresponding conductivity in these compounds. Here, we report first-principles-based atomistic simulations that predict that the transverse (polarization-related) displacement currents of 71° and 109° domains in the prototypical BiFeO₃ multiferroic material are significant at the walls of such domains and in the GHz regime, and, in fact, result in currents that are at least of the same order of magnitude than previously reported dc currents (that are likely extrinsic in nature and due to electrons). Such large, localized and intrinsic ac currents are found to originate from low-frequency vibrations at the domain walls, and may open the door to the design of novel devices functioning in the GHz or THz range and in which currents would be confined within the domain wall.

1861年，麦克斯韦（Maxwell）提出了位移电流的概念，这使电动力学定律更加完善，并最终实现了利用这种位移电流的设备的实现。有趣的是，尽管最近有大量活动致力于磁畴及其在这些化合物中的相应电导率，但目前尚不知道这种置换电流是否会在具有磁畴的铁体系中产生大的固有交流电流。在这里，我们报告基于第一原理的原子模拟，该模拟预测原型BiFeO ₃中71°和109°域的横向（极化相关）位移电流多铁性材料在这种区域的壁上以及在GHz范围内都非常重要，并且实际上导致的电流至少比以前报告的dc电流大小相同（本质上可能是非本征的，而且是由于电子引起的） ）。发现如此大的，局部的和固有的交流电流源自磁畴壁的低频振动，这可能为设计工作在GHz或THz范围内且电流将被限制在该磁畴内的新型设备打开了大门。墙。