Wireless technology relies on the conversion of alternating electromagnetic fields into direct currents, a process known as rectification. Although rectifiers are normally based on semiconductor diodes, quantum mechanical non-reciprocal transport effects that enable a highly controllable rectification were recently discovered^{1,2,3,4,5,6,7,8,9}. One such effect is magnetochiral anisotropy (MCA)^6,7,8,9, in which the resistance of a material or a device depends on both the direction of the current flow and an applied magnetic field. However, the size of rectification possible due to MCA is usually extremely small because MCA relies on inversion symmetry breaking that leads to the manifestation of spin–orbit coupling, which is a relativistic effect^6,7,8. In typical materials, the rectification coefficient γ due to MCA is usually ∣γ∣ ≲ 1 A⁻¹ T⁻¹ (refs. ^8,9,10,11,12) and the maximum values reported so far are ∣γ∣ ≈ 100 A⁻¹ T⁻¹ in carbon nanotubes¹³ and ZrTe₅ (ref. ¹⁴). Here, to overcome this limitation, we artificially break the inversion symmetry via an applied gate voltage in thin topological insulator (TI) nanowire heterostructures and theoretically predict that such a symmetry breaking can lead to a giant MCA effect. Our prediction is confirmed via experiments on thin bulk-insulating (Bi_1−xSb_x)₂Te₃ (BST) TI nanowires, in which we observe an MCA consistent with theory and ∣γ∣ ≈ 100,000 A⁻¹ T⁻¹, a very large MCA rectification coefficient in a normal conductor.

无线技术依赖于将交流电磁场转换为直流电，这一过程称为整流。尽管整流器通常基于半导体二极管，但最近发现了能够实现高度可控整流的量子力学非互易传输效应^{1,2,3,4,5,6,7,8,9}。一种这样的效应是磁手性各向异性 (MCA) ^6,7,8,9，其中材料或设备的电阻取决于电流的方向和施加的磁场。然而，由于 MCA 可能导致的整流大小通常非常小，因为 MCA 依赖于反转对称性破坏，导致自旋轨道耦合的表现，这是一种相对论效应^6,7,8. 在典型材料中，由 MCA 引起的整流系数γ通常为∣ γ ∣  ≲  1 A ^-1  T ^-1（参考文献^{8、9、10、11、12}），迄今为止报道的最大值为∣ γ ∣  ≈ 100碳纳米管¹³和 ZrTe ₅中的 A ^-1  T ^-1（参考文献¹⁴）。在这里，为了克服这一限制，我们通过在薄拓扑绝缘体 (TI) 纳米线异质结构中施加栅极电压人为地破坏反转对称性，并从理论上预测这种对称性破坏会导致巨大的 MCA 效应。我们的预测通过对薄体绝缘 (Bi _{1− x} Sb _x ) ₂ Te ₃ (BST) TI 纳米线的实验得到证实，其中我们观察到与理论一致的 MCA 和∣ γ ∣  ≈ 100,000 A ^-1  T ^-1，正常导体中非常大的 MCA 整流系数。