Organic Control of Topological Surface States for THz Logic

拓扑绝缘体是一类特殊的材料，由于能带反转而表现出导电表面状态。这种表面态具有显著的性质，包括自旋动量锁定和狄拉克费米子的近无损输运。这些材料在计算、传感和太赫兹通信方面具有丰富的应用。拓扑表面状态可以通过使用有机掺杂剂进行主动控制，为通信、传感和量子技术提供低损耗、高速电子器件的途径。项目将分三个阶段进行。首先，将与利兹大学合作开发融合拓扑绝缘体和有机半导体的混合材料，并使用格拉斯哥开尔文纳米表征中心和SuperSTEM的电子显微镜进行分析。我们将建立生长工艺，以生产高绝缘的TI材料，bbte，涂覆高结晶层的C60，以及有机分子，如Cu-Pthalocyanine。在第二阶段，我们将分析这些材料的表面状态，寻找拓扑表面状态的特征及其被有机物修饰的特征。在第三阶段，我们将把这些材料制成纳米天线，以便使用电子能量损失谱分析表面态的等离子体特性。到项目结束时，我们将牢固地建立一个新的范例来设计拓扑绝缘体的表面状态。到目前为止，由于沉积困难，有机半导体和ti尚未集成到单个器件中，并且无法用于修改现实器件中的表面状态。利兹大学的罗伊斯沉积系统解决了这个问题。通过将利兹大学的材料专业知识与格拉斯哥大学世界领先的电子显微镜相结合，我们可以探索这种全新的混合材料，并从中开发出新的设备概念。该项目旨在通过在有源设备中利用极低损耗的传输机制来减少通信和计算基础设施的能耗。这是通过开发利用新型凝聚态物理的先进功能材料来实现的。这些器件最终将应用于光子电路，并有可能应用于集成光子学和自旋电子学的器件。该项目由高级材料讲师兼皇家工程院院士Timothy Moorsom博士和材料与凝聚态物理组高级讲师Donald MacLaren博士监督。该项目涉及用于等离子体应用的拓扑-绝缘体-有机混合器件的制造和表征。他们将利用詹姆斯瓦特纳米制造中心的洁净室设施以及开尔文纳米表征中心的电子显微镜设备，用最先进的设备开发尖端技术。除了在格拉斯哥大学的工作，他们还将利用位于利兹大学的亨利·罗伊斯研究所的多功能MBE来培育新型拓扑材料。学生还将有机会参加在卢瑟福·阿普尔顿实验室、苏黎世的保罗·谢勒研究所和巴塞罗那的ALBA同步加速器等国内和国际设施进行的合作实验。

SummaryTopological Insulators are a special class of materials which exhibit a conducting surface state as a consequence of band inversion. This surface state has remarkable properties, including spin-momentum locking and near lossless transport of Dirac fermions. These materials have a wealth of applications in computing, sensing and THz communications. Topological surface states can be actively controlled through the use of organic dopants, providing a route towards low-loss, high speed electronics for communications, sensing and quantum technologies.ObjectivesThe project will proceed in three stages. Firstly, hybrid materials fusing topological insulators and organic semi-conductors will be developed through collaboration with Leeds University, and analysed using the electron microscopes in the Kelvin Nano-Characterisation Centre at Glasgow and at SuperSTEM. We will establish growth processes to produce the highly insulating TI material, BiSbTe, coated with highly crystalline layers of C60, as well as organic molecules such as Cu-Pthalocyanine. In the second phase, we will analyse the surface states of these materials, looking for signatures of topological surface states and their modification by organics. In the third phase, we will pattern these materials into nano-antennae, in order to analyse the plasmonic characteristics of the surface states using electron energy loss spectroscopy.NoveltyBy the end of the project, we will have firmly established a new paradigm for engineering the surface states of topological insulators. Until now, organic semiconductors and TIs have not been integrated into a single device due to the difficulty of deposition, and could not be used to modify surface states in realistic devices. This has now been solved by the creation of the Royce Deposition System at the University of Leeds. By combining the materials expertise of Leeds with world leading electron microscopes at Glasgow, we can explore this entirely novel class of hybrid materials and develop new device concepts from them.Alignment and StrategyThis project aims to reduce energy consumption of communication and computational infrastructure by utilising extremely low-loss transport regimes in active devices. This is achieved through the development of advanced functional materials that take advantage of novel condensed matter physics. These devices will ultimately be applied in photonic circuits and potentially in devices that integrate photonics and spintronics.CollaborationsThe project is supervised by Dr Timothy Moorsom, Lecturer in Advanced Materials and Royal Academy of Engineering Fellow, and Dr Donald MacLaren, Senior Lecturer, in the Materials and Condensed Matter Physics group. The project involves the fabrication and characterisation of topological-insulator-organic hybrid devices for plasmonic applications. They will utilise the James Watt Nanofabrication Centre cleanroom facilities as well as the Kelvin Nanocharacterisation Centre's electron microscopy equipment, developing cutting edge skills with state-of-the-art equipment. In addition to work at the University of Glasgow, they will utilise the Henry Royce Institute's multifunctional MBE, at the University of Leeds, to grow novel topological materials. There will also be opportunities to take part in collaborative experiments at national and international facilities suchas the Rutherford Appleton Laboratory, the Paul Scherrer Institute in Zurich and the ALBA synchrotron in Barcelona.