Agile electronics through ferroelectric switching of two-dimensional materials

不同二维材料的原子薄层可以以原子精度堆叠以创建二维异质结构（2D- hs）。例如，这导致了更高效发光二极管的设计，以及石墨烯中绝缘到超导转变等新现象的研究。在这些异质结构中，垂直于层的电场可用于设计能带排列，控制载流子浓度，甚至在金属，绝缘和超导状态之间切换。这些场通常由预先定义的金属电极引起，这些电极可以控制场强，但具有固定的（微尺度）几何形状，动态响应有限。该项目将开发一种替代方法。在铁电钙钛矿氧化物薄膜表面可以形成强电场，电场具有纳米级精度。磁场的极性可以快速切换，甚至磁场的空间排列也可以动态控制。这提供了一个令人兴奋的机会，通过将钙钛矿铁电体集成到2d - hs中来创建灵活的电子产品。创建这样一个强大的平台，以静电定义2dm中的绝缘和导电区域，并动态切换其导电性，将使我们能够探索新的物理现象并开发新的电子功能。该项目的目的是探索新的人工异质结构系统，将超薄铁电体与2dm结合起来，特别是2D范德华半导体，利用降维和界面相互作用来控制这些人工材料的性能和工程新功能。该项目将重点开发控制2d - hs与沃里克大学通过脉冲激光沉积生长的高质量钙钛矿薄膜氧化物之间界面的技术。仔细描述这个界面，以及它对2d - hs电子特性的影响，对于项目的更广泛成功至关重要。这项研究将利用华威大学优秀的显微镜和光谱学基础设施，以及国际同步加速器设施。它与EPSRC资助的响应模式授权EP/T027207/1紧密相关，用于敏捷和可重构2D电子设备的铁电门控。

Atomically thin layers of different two-dimensional materials can be stacked with atomic precision to create 2D heterostructures (2D-HS). This has led to the design of more efficient light emitting diodes for example, and the study of new phenomena such as an insulating to superconducting transition in graphene. In these heterostructures, electric fields perpendicular to the layers can be used to engineer the band alignments, control carrier concentrations, and even switch between metallic, insulating and superconducting states. These fields are usually induced by predefined metallic electrodes which give control over the field strength but are of fixed (microscale) geometry and have limited dynamic response. This project will develop an alternative approach. Strong electric fields can be formed at the surface of thin-film ferroelectric perovskite oxides, with the field patterned with nanoscale precision. The polarity of the field can be switched rapidly and even the spatial arrangement of the field can be controlled dynamically. This presents an exciting opportunity to create agile electronics by integrating perovskite ferroelectrics into 2D-HSs. Creating such a robust platform for electrostatically defining insulating and conducting regions in 2DMs, and for dynamically switching their conductivity, will allow us to explore new physical phenomena and to develop new electronic functionalities. The aim of this project is to explore new artificial heterostructure systems that combine ultrathin ferroelectrics with 2DMs, especially 2D van-der-Waals semiconductors, exploiting reduced dimensionality and interfacial interactions to control the properties and engineer new functionalities in these artificial materials. The project will focus on developing techniques for controlling the interface between the 2D-HSs and high-quality thin-film perovskite oxides grown at Warwick by pulsed laser deposition. Careful characterisation of this interface, and its effect on the electronic properties of the 2D-HSs, will be essential to the wider success of the project. The research will make use of the excellent microscopy and spectroscopy infrastructure at the University of Warwick, as well as international synchrotron-based facilities. It is tied closely to the EPSRC funded responsive mode grant EP/T027207/1, Ferroelectric gating for agile and reconfigurable 2D electronics.