Domain walls in ferroelectric semiconductors show promise as multifunctional two-dimensional elements for next-generation nanotechnology. Electric fields, for example, can control the direct-current resistance and reversibly switch between insulating and conductive domain-wall states, enabling elementary electronic devices such as gates and transistors. To facilitate electrical signal processing and transformation at the domain-wall level, however, an expansion into the realm of alternating-current technology is required. Here, we demonstrate diode-like alternating-to-direct current conversion based on neutral ferroelectric domain walls in ErMnO₃. By combining scanning probe and dielectric spectroscopy, we show that the rectification occurs at the tip–wall contact for frequencies at which the walls are effectively pinned. Using density functional theory, we attribute the responsible transport behaviour at the neutral walls to an accumulation of oxygen defects. The practical frequency regime and magnitude of the direct current output are controlled by the bulk conductivity, establishing electrode–wall junctions as versatile atomic-scale diodes.

铁电半导体中的畴壁显示出有望作为下一代纳米技术的多功能二维元件。例如，电场可以控制直流电阻，并在绝缘和导电畴壁状态之间可逆地切换，从而使诸如栅极和晶体管之类的基本电子设备成为可能。但是，为了便于在域壁级别进行电信号处理和转换，需要扩展到交流技术领域。在这里，我们演示了基于ErMnO _3中的中性铁电畴壁的类似二极管的交流电到直流电的转换。通过结合使用扫描探针和介电谱，我们显示出整流作用发生在针尖与壁的接触点上，从而有效地固定了壁的频率。使用密度泛函理论，我们将中性壁处负责任的传输行为归因于氧缺陷的积累。实际的频率范围和直流输出的大小受整体电导率的控制，从而将电极-壁结建立为通用的原子级二极管。