MACROSCOPIC PHASE COHERENCE FROM SYNTHETIC INTERLAYER COUPLING IN VAN DER WAALS FLAT BANDS

范德瓦尔斯平带中合成层间耦合的宏观相位相干性

• 批准号: 2226850
• 负责人: Andrea Young
• 金额: $ 44.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-15 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2226850&HistoricalAwards=false
• 关键词: MACROSCOPIC; PHASE; COHERENCE; SYNTHETIC; INTERLAYER

Non-technical description: Many spectacular physical phenomena—and useful device—rely on macroscopic quantum coherence. The most well known example are superconductors, where macroscopic coherence is directly tied both the absence of electrical resistance as well as the emergence of coherent degrees of freedom that form the basis for the best developed platforms for manipulating quantum information. However, macroscopic quantum coherence, in principle, a much broader phenomenon. This project aims to realize new modalities of macroscopic quantum coherence in a broad class of materials known as van der Waals heterostructures. Van der Waals heterostructures consist of successively laminated two dimensional atomic crystals such as graphene; their high crystalline perfection and broad range of tunability put a variety of new quantum coherent states in experimental range. By realizing new states characterized by macroscopic quantum coherence, this project furthers understanding of these phenomena and opens new avenues towards quantum information processing. Synergistic with the research effort is an educational initiative focused on technical workforce development, implemented through a summer school for graduate student across physics, chemistry and materials science working on quantum science related problems. Technical description:The ultimate goal of this project is to create a novel quantum bit based on interlayer coherence in a bilayer exciton condensate. This bit exploits the spontaneous phase coherence predicted to occur in these systems. Bilayer exciton condensates, first discovered in semiconductor quantum wells, have recently been shown to exist in graphene and chalcogenide heterostructures at higher temperatures and under less demanding experimental conditions—particularly in the absence of magnetic fields. The research team is using frequency-dependent interlayer tunneling spectroscopy to directly detect the emergence of macroscopic phase coherence through the excitonic analog of the AC Josephson effect. This new detection modality then allows a broad search for macroscopic coherence in a variety of double layer structures based on band-structure engineered two dimensional double layers.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.

非技术描述：许多壮观的物理现象和有用的设备都依赖于宏观量子相干性，最著名的例子是超导体，其中宏观相干性与电阻的缺失以及相干自由度的出现直接相关。然而，宏观量子相干性原则上是一种更广泛的现象，旨在在广泛的材料中实现宏观量子相干性的新模式。范德华异质结构由连续层压的二维原子晶体组成，例如石墨烯；它们的高结晶完美性和广泛的可调性使各种新的量子相干态处于实验范围内。宏观量子相干性，该项目加深了对这些现象的理解，并为量子信息处理开辟了新的途径。与研究工作的协同是一项专注于技术劳动力发展的教育计划，通过暑期学校实施。适用于研究量子科学相关问题的物理、化学和材料科学的研究生 技术描述：该项目的最终目标是创建一种基于双层激子凝聚体中的层间相干性的新型量子位。双层激子凝聚首次在半导体量子阱中发现，最近已被证明在较高温度和不太苛刻的实验条件下存在于石墨烯和硫族化物异质结构中，特别是在研究小组正在使用频率相关的层间隧道光谱，通过交流约瑟夫森效应的激子模拟来直接检测宏观相位相干性的出现，然后这种新的检测方式可以对宏观相干性进行广泛的搜索。基于能带结构工程二维双层的各种双层结构。该奖项反映了 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。