Observation of the antiferromagnetic diode effect

In a PN junction, the separation between positive and negative charges leads to diode transport, which is the foundation for nonlinear applications such as rectification and wave mixing. In the past few years, the intrinsic diode transport in noncentrosymmetric polar conductors has attracted great interest, because it suggests novel nonlinear applications and provides a symmetry-sensitive probe of Fermi surface electrons. More recently, such studies have been extended to noncentrosymmetric polar superconductors, realizing the superconducting diode effect. Here, we show that, even in a centrosymmetric crystal without directional charge separation, the spins of an antiferromagnet (AFM) can generate a clear spatial directionality, leading to an AFM diode effect. In the 2D even-layered MnBi2Te4, we observe a large nonlinear transport signal in the fully compensated AFM state. We demonstrate that, based on this effect, the AFM enables an in-plane field effect transistor and the harvesting of wireless electromagnetic energy. Our observation paves the way for AFM logic circuits, self-powered AFM spintronic devices, and other intriguing applications that bridge nonlinear electronics with AFM spintronics.