Schaab Jakob, Skjærvø Sandra H, Krohns Stephan, Dai Xiaoyu, Holtz Megan E, Cano Andrés, Lilienblum Martin, Yan Zewu, Bourret Edith, Muller David A, Fiebig Manfred, Selbach Sverre M, Meier Dennis
Department of Materials, ETH Zurich, Zurich, Switzerland.
Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
Nat Nanotechnol. 2018 Nov;13(11):1028-1034. doi: 10.1038/s41565-018-0253-5. Epub 2018 Sep 10.
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 ErMnO. 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有望成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切换，从而实现诸如栅极和晶体管等基本电子器件。然而，为了在畴壁层面促进电信号处理和转换，需要拓展到交流技术领域。在此，我们展示了基于ErMnO中中性铁电畴壁的类似二极管的交流到直流转换。通过结合扫描探针和介电谱，我们表明，在壁被有效固定的频率下，整流发生在针尖-壁接触处。利用密度泛函理论，我们将中性壁处的负责输运行为归因于氧缺陷的积累。直流输出的实际频率范围和幅度由体电导率控制，将电极-壁结确立为通用的原子尺度二极管。
