Imaging correlations and charge order in transition metal dichalcogenide moiré systems

过渡金属二硫属化物莫尔系统中的成像相关性和电荷顺序

• 批准号: 2103910
• 负责人: Benjamin Feldman
• 金额: $ 45万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2103910&HistoricalAwards=false
• 关键词: Imaging; correlations; charge; order; transition

Non-technical abstract: The electronic properties of materials are governed by the arrangement of atoms and electrons within them. In most cases, this is fixed by the chemistry of the constituent atoms. However, recent advances in the ability to isolate atomically thin crystals and stack them on top of each other provide a route to engineer new synthetic materials. This project investigates how adding a small twist between adjacent layers can be used to control the positions and propagation of electrons. In particular, the rotational misalignment causes the electrons to interact especially strongly with each other, leading to new quantum electronic properties. The research uses a nanoscale sensor to image the resulting electron positions, study the new quantum states that form, and determine the degree to which they can be controlled. The predicted states may have applications in low-power electronics, fault-tolerant quantum computing, and high-density data storage. The project also trains undergraduate and graduate students for careers in quantum technology, fosters the involvement of underrepresented groups in science through summer internships, and inspires the next generation of researchers by developing and implementing outreach activities for high school students and local science festivals.Technical Abstract: Stacking van der Waals materials with similar lattice constants at small relative twist angle can generate exceptionally flat electronic bands that are susceptible to strong Coulomb interactions. This project aims to investigate the plethora of many-body phases that can be realized in twisted devices composed from semiconducting transition metal dichalcogenides (TMDs). The research uses a scanning single-electron transistor (SET) to measure local electronic compressibility and to image charge distribution in moiré TMD systems. The primary goals include: 1) measuring the energy gaps and excitations of correlated electronic ground states; 2) imaging charge ordered phases, such as stripes and generalized Wigner crystals and their melting; and 3) probing the dependence of these emergent states on magnetic field, doping, and twist angle to map out the triangular Hubbard model phase diagram. Moiré TMD systems provide unprecedented flexibility for quantum simulation across a wide swath of Hubbard model parameter space. As a local thermodynamic probe of electronic properties, the SET provides unique insight into this strongly correlated materials platform. In addition, graduate and undergraduate students gain experience in the area of van der Waals assembly and low-temperature scanning probe microscopy.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.

非技术摘要：材料的电子特性由其内部原子和电子的排列决定，但在大多数情况下，这是由组成原子的化学性质决定的。然而，最近在分离原子级薄晶体和电子的能力方面取得了进展。将它们堆叠在一起为设计新的合成材料提供了一条途径，该项目研究了如何在相邻层之间添加小扭曲来控制电子的位置和传播，特别是旋转失准会导致电子相互作用。特别强烈地该研究使用纳米级传感器对由此产生的电子位置进行成像，研究形成的新量子态，并确定它们的控制程度。预测的状态可能在低水平下有应用。 -电力电子、容错量子计算和高密度数据存储该项目还为本科生和研究生提供量子技术职业培训，通过暑期实习促进代表性不足的群体参与科学，并激励下一代研究人员。通过制定和实施高水平的外展活动技术摘要：以较小的相对扭转角堆叠具有相似晶格常数的范德华材料可以产生非常平坦的电子带，这些电子带容易受到强库仑相互作用的影响。该项目旨在研究过多的多体相。该研究使用扫描单电子晶体管（SET）来测量局部电子压缩性并对电荷分布进行成像。主要目标包括：1) 测量相关电子基态的能隙和激发；2) 成像电荷有序相，例如条纹和广义维格纳晶体及其熔化；3) 探测它们的依赖性；磁场、掺杂和扭转角的涌现状态来绘制三角形莫尔TMD 模型相图，为跨广泛的哈伯德模型参数的量子模拟提供了前所未有的灵活性。作为电子特性的本地热力学探针，SET 提供了对这种强相关材料平台的独特见解。此外，研究生和本科生还可以获得范德华组装和低温扫描探针显微镜领域的经验。该奖项体现了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。