Investigation and control of 2D-3D interfacial states

非技术描述：本项目旨在实验研究新观察到的层状材料（如石墨烯）和块状半导体（如硅树脂）异质结的界面量子态。这些新出现的状态与层状或块状材料的固有电子结构无关，而是一种新的界面效应，丰富了我们目前对低维固态系统的理解。这项研究为符合国家量子倡议法案的新型电子、光电和量子技术开辟了人工量子结构的替代途径。科学成果通过期刊、会议和特邀演讲传播。更重要的是，该项目的研究机构佐治亚州立大学是一所历史悠久的少数民族服务机构和一流的创新型教学大学。许多本科生和研究生，尤其是代表性不足的少数群体，将被纳入这项前沿研究，为他们在科学、技术、工程和数学领域的职业生涯做好准备。本科生通常会继续学习STEM研究生课程。研究生通常在大学、国家实验室和联邦研究机构继续他们的学术生涯，或者成为半导体、信息技术等行业的领导者。此外，该项目通过开放日、讲座、暑期实习等方式，将大亚特兰大地区暴露在现代量子科学技术的前沿，使公众和K-12学生能够接触到最先进的技术和最新的科学进展。技术描述：层状材料异质结构的制造有助于人工量子相互作用的构建，否则在固有材料中是无形的。目前，这些新兴结构中的大多数都是用平面内电子相互作用的成熟框架来解释的，而最近由PI发现的石墨烯-硅结的共振隧道行为表明，面外量子态的存在源于界面上的突然维度变化。这一新发现刷新了对降维材料的理解，并赋予了人工量子结构的新设计，因此，有必要立即对这些状态的形成机制和控制方法进行彻底的研究。为此，本研究主要采用隧道光谱作为首次实验尝试，以确定这些状态的决定因素，包括横向动量失配，晶格取向和结的介电性质。随后，温度相关测量和原位原子/分子吸附实验也揭示了声子/缺陷诱导的散射和非弹性隧道过程，以探索这些面外态的弛豫。对这些主题的研究使新型量子器件的构建成为可能，包括多层多阱共振隧道晶体管和共振分子探测器，以展示该项目的转变潜力。这些努力丰富了我们对降维异质结构上界面量子相互作用的理解，同时为太赫兹光源和探测器、级联光电子学以及许多其他电子、光电和量子体系结构的设计提供了广泛的新策略。此外，该项目还为参与的研究生、本科生和实习生提供广泛的培训和教育，以加速他们在凝聚态物理和量子科学方面的职业发展轨迹。促进现代量子科学技术的公众教育。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical description: This project aims to experimentally investigate newly observed interfacial quantum states on heterojunctions of layered materials (e.g., graphene) and bulk semiconductors (e.g., silicone). These emerging states are independent of the intrinsic electronic structures of either the layered or bulk materials, but a novel interfacial effect, which enriches our current understanding of low-dimensional solid-state systems. This study opens alternative pathways towards artificial quantum structures for novel electronic, optoelectronic, and quantum technologies that are in line with the National Quantum Initiative Act. The scientific outcomes are disseminated via journals, conferences, and invited talks. More importantly, the research institute of this project, Georgia State University, is a historically minority-serving institution and top-ranked innovative teaching university. Many undergraduate and graduate students, especially underrepresented minority groups will be included in this cutting-edge research and prepare them for careers in science, technology, engineering, and mathematics. Undergraduate students typically continue their study in STEM graduate programs. Graduate students usually pursue their academic careers in universities, national laboratories, and federal research institutions or become leaders in the industries of semiconductors, information technology, etc. Furthermore, the project exposes the Greater Atlanta Area to the frontier of modern quantum science and technology via open houses, talks, summer internships so that the public and K-12 students get access to the state-of-the-art technology and latest scientific progress along with this research. Technical description: Fabrication of layered material heterostructures facilitates the construction of artificial quantum interactions, otherwise intangible in intrinsic materials. Currently, most of these emerging structures are interpreted by the well-established framework of in-plane electronic interactions, whereas a resonant tunneling behavior of graphene-silicon junctions recently discovered by the PI suggests the existence of out-of-plane quantum states, which is originated from an abrupt dimensional change on the interfaces. This new observation refreshes the understanding of reduced-dimensional materials and empowers new designs of artificial quantum structures, as such, necessitates a thorough investigation on the formation mechanism and control methods of these states without delay. For this purpose, this study primarily employs tunneling spectroscopy as the first experimental attempt to identify the determinative factors of these states, including transverse momentum mismatch, lattice orientations, and dielectric properties of the junctions. Following that, temperature-dependent measurements and in-situ atomic/molecular adsorption experiments also unveil the phonon-/defect-induced scattering and inelastic tunneling processes to explore the relaxation of these out-of-plane states. The investigation on these topics enables the construction of novel quantum devices, including layered multiple-well resonant tunneling transistors and resonant molecular detectors, to showcase the transformational potentials of this project. These efforts enrich our comprehension of the interfacial quantum interactions on reduced-dimensional heterostructures, meanwhile envision a breadth of new strategies for the design of terahertz light sources and detectors, cascade optoelectronics, and many other electronic, optoelectronic, and quantum architectures. Furthermore, the project is accompanied by extensive training and education for participating graduate, undergraduate students, and interns to accelerate their career trajectories in condensed matter physics and quantum science. It also promotes the public education of modern quantum science and technology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.