CAREER: Correlated Excitons in Semiconducting Moire Superlattices

职业：半导体莫尔超晶格中的相关激子

• 批准号: 2337606
• 负责人: CHENHAO JIN
• 金额: $ 75.03万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-01 至 2029-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2337606&HistoricalAwards=false
• 关键词: CAREER; Correlated; Excitons; Semiconducting; Moire

Non-technical abstract:Fundamental particles can be classified into fermions and bosons, which have distinct collective behaviors. Interactions between electrons, a fermion, results in now well known emergent properties. On the other hand, creation of unconventional bosonic matter has been challenging since bosons in natural materials are often weakly-interacting and/or short-lived. This project bridges this gap by creating unconventional bosonic matter using excitons in semiconducting moiré superlattices. Compared to existing platforms such as cold atoms and quantum wells, this platform offers orders-of-magnitude higher temperature scale (tens of Kelvin vs. 1 Kelvin) and scalability (10000 particles vs. ~100 particles). Research is incorporated into a broad outreach plan under the theme of “Science as a Lego game”. Leveraging the Lego-like nature of optical setups, integrated outreach activities are targeted at students at many educational levels to demystify quantum science and introduce them to potential career options. Specific activities include designing a high-school lab-based class series on building optical modules and a Saturday class on optics in quantum science; initiating a summer research intern program for undergraduate students; and organizing a quantum science summer school for graduate students and postdocs.Technical abstract:Condensed matter physics aims to understand how interactions endow simple elementary particle building blocks with complex emergent phenomena. Exotic quantum phases of fermionic electrons have been intensively studied in solid-state systems, including recently in moiré superlattices. However, collective bosonic states have remained the purview of ultra-cold atoms due to the lack of suitable condensed matter platforms and experimental probes. This project aims to overcome both challenges and establishe excitons in semiconducting moiré superlattices -- bosons composed of tightly bound electron-hole pairs -- as a platform for engineering exotic collective states of interacting bosons. The principal investigator is developing a set of novel pump- probe spectroscopies that enables direct measurement of exciton compressibility, isolating low energy “charge” and “spin” excitations of excitons, as well as investigating their dynamics. This allows identification and investigation of a plethora of exotic bosonic phases such as bosonic Wigner crystal, Mott-superfluid transition, valley pseudospin exchange interactions and pseudospin orders, etc. This project forges a path to a new class of “quantum exitonic materials” where exotic properties and novel device concepts arise from strongly correlated bosons, thereby establishing a new fundamental pillar of condensed matter alongside the extensively studied quantum electronic materials.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：基本粒子可以分为费米子和玻色子，它们具有不同的集体行为。电子之间的相互作用，费米子，导致现在众所周知的涌现性质。另一方面，非常规玻色子物质的创造一直具有挑战性，因为自然材料中的玻色子通常相互作用较弱和/或寿命较短。这个项目通过在半导体莫尔超晶格中使用激子来创造非传统的玻色子物质来弥合这一差距。与现有的平台，如冷原子和量子威尔斯，这个平台提供了数量级更高的温度范围（几十开尔文对1开尔文）和可扩展性（10000粒子对~100粒子）。研究工作被纳入一项广泛的外联计划，主题是“科学是一种乐高游戏”。利用光学设置的乐高性质，综合推广活动针对许多教育水平的学生，以揭开量子科学的神秘面纱，并向他们介绍潜在的职业选择。具体活动包括设计一个高中实验室为基础的系列课程，建立光学模块和周六班的光学在量子科学;启动一个夏季研究实习生计划的本科生;并组织一个量子科学暑期学校的研究生和博士后。技术摘要：凝聚态物理学的目的是了解如何相互作用赋予简单的基本粒子积木与复杂的涌现现象。费米子电子的奇异量子相位在固态系统中得到了深入的研究，包括最近在莫尔超晶格中。然而，由于缺乏合适的凝聚态平台和实验探针，集体玻色子态一直是超冷原子的研究领域。该项目旨在克服这两个挑战，并在半导体莫尔超晶格中建立激子-由紧密结合的电子-空穴对组成的玻色子-作为工程相互作用玻色子的奇异集体状态的平台。主要研究者正在开发一套新颖的泵浦-探测光谱，能够直接测量激子的可压缩性，隔离激子的低能“电荷”和“自旋”激发，以及研究它们的动力学。这使得我们能够识别和研究大量的奇异玻色子相，如玻色子维格纳晶体、莫特超流跃迁、谷赝自旋交换相互作用和赝自旋序等。该项目为一类新的“量子激子材料”开辟了一条道路，其中奇异的性质和新颖的器件概念来自强关联玻色子，该奖项反映了美国国家科学基金会的法定使命，并通过利用基金会的智力价值进行评估，被认为值得支持和更广泛的影响审查标准。