Topological Graphene Multiterminal Josephson Junctions

拓扑石墨烯多端约瑟夫森结

• 批准号: 467596333
• 负责人: Professor Dr. Detlef Beckmann
• 金额: --
• 依托单位: Arbeitsgruppe Theorie des Quantentransports
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/467596333?language=en
• 关键词: Topological; Graphene; Multiterminal; Josephson; Junctions

Topological properties of quantum systems have recently attracted considerable theoretical and experimental attention. Nontrivial topological properties usually follow from intrinsic material properties, e.g., topological band structures in materials with strong spin-orbit interaction. Another possibility is the combination of different materials in hybrid structures to create topological band structures. These implementations require complex materials which are often difficult to synthesize.Recently, it has been predicted that multiterminal Josephson junctions made of conventional materials host topologically nontrivial states in an artificial band structure controlled by the macroscopic phases of the superconducting terminals. These systems offer the possibility to tune topological properties in situ by external parameters, and therefore allow considerable flexibility for the investigation of topology.The aim of this project is a joint experimental and theoretical effort to implement and understand artificial topological band structures in multiterminal Josephson junctions. The material of choice for our project is graphene. Due to its two-dimensional nature, graphene offers full flexibility of design, while its intrinsic high quality and gate tunability allows control of ballistic transport down to single quantum channels. Therefore, graphene is a prime candidate for the investigation of topological multiterminal Josephson junctions. We plan to unambiguously identify and characterize topological Andreev states via quantized nonlocal conductance and microwave spectroscopy in a minimal system, a four-terminal Josephson junction. A long-term goal is to use graphene multiterminal junctions to simulate topology in higher effective dimensions.

量子系统的拓扑特性最近引起了相当大的理论和实验性关注。非平凡的拓扑特性通常来自内在的材料特性，例如具有强旋转轨道相互作用的材料中的拓扑带结构。另一种可能性是混合结构中不同材料的组合，以创建拓扑结构。这些实现需要复杂的材料，通常很难合成。实际上，已经预测，由常规材料制成的多端约瑟夫森连接在人工谱带结构中由超导末端的宏观阶段控制的人造带结构中。这些系统提供了通过外部参数原位调节拓扑特性的可能性，因此可以进行拓扑调查的灵活性。该项目的目的是在多性约瑟夫森（Josephson）连接中实施和理解人工拓扑结构的联合实验和理论上的努力。我们项目的首选材料是石墨烯。由于其二维性质，石墨烯提供了设计的完全灵活性，而其内在的高质量和门可调性允许控制弹道传输到单个量子通道。因此，石墨烯是研究多端约瑟夫森连接的主要候选者。我们计划通过在最小的系统（一个四末端的约瑟夫森连接处）中量化的非本地电导和微波光谱来明确识别和表征拓扑的Andreev状态。一个长期的目标是使用石墨烯多发连接来模拟更高的有效尺寸的拓扑。