Moiré enhanced infrared photodetection and THz emission in twisted graphene superlattices

莫尔增强扭曲石墨烯超晶格中的红外光电探测和太赫兹发射

• 批准号: 471733165
• 负责人: Professor Dr. Christoph Stampfer
• 金额: --
• 依托单位: Institut für Quantenelektronik
• 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/471733165?language=en
• 关键词: Moir; enhanced; infrared; photodetection; THz

Light-matter interactions underlies the operation of modern optoelectronics. In the past decade, graphene and related 2D materials (GRMs) have shown great promise in the field of optoelectronics including gate-tuneable modulation, ultra-fast detection and THz capabilities. Graphene itself exhibits weak optical absorption (2.3 %) and exploiting its broadband optical response relies on the integration of extrinsic device architectures. By contrast, twisted bilayer graphene (TBG) superlattices exhibit strikingly different properties as the moiré superlattice potential strongly modifies the band structure, creating exceptionally narrow energy bands and spectral gaps in the range 10-100 meV. Consequently, their intrinsic optical conductivity exhibits a strong mid-infrared and terahertz (THz) response thanks to the moiré induced electronic reconstruction. Combined with other unique properties such as exceptionally high density of states and in-situ tuneable topological bands make TBG an promising candidate for a new generation of infrared and THz optoelectronic devices. The project PhotoTBG aims to study the fundamental light-matter interactions of TBG in the linear and non-linear response regime. The first goal is to study the intrinsic infrared and THz photoconductivity of TBG in the linear response regime, uncovering novel mechanisms for electrical tuneability and photoexcitation enhanced by topology. The second effort focuses on the highly biased regime in search for Bloch oscillations – one of the oldest and yet most elusive phenomena in condensed matter physics – paving the way for a new generation of THz sources.

光与物质的相互作用是现代光电子学运行的基础。在过去的十年里，石墨烯及其相关的2D材料(GRM)在光电子学领域显示出巨大的前景，包括栅极可调谐调制、超快探测和太赫兹能力。石墨烯本身表现出弱的光吸收(2.3%)，利用其宽带光学响应依赖于外部器件架构的集成。相比之下，扭曲的双层石墨烯(TBG)超晶格表现出惊人的不同性质，因为莫尔超晶格势强烈地改变了能带结构，在10-100 meV范围内产生了非常窄的能带和光谱带隙。因此，由于莫尔诱导的电子重构，它们的本征光学电导表现出很强的中红外和太赫兹(THz)响应。结合了其他独特的性质，如异常高的态密度和可就地调节的拓扑带，使得TBG成为新一代红外和THz光电子器件的候选材料。PhotoTBG项目旨在研究在线性和非线性响应区域中TBG的基本光-物质相互作用。第一个目标是研究TBG在线性响应区的本征红外和THz光电导，揭示通过拓扑增强电可调谐和光激发的新机制。第二项工作聚焦于寻找布洛赫振荡的高度偏向机制--这是凝聚态物理学中最古老、也是最难以捉摸的现象之一--为新一代太赫兹源铺平了道路。