CAREER: Probing exciton-exciton correlations and phase transitions for spin-polarized excitons in monolayer transition metal dichalcogenides

职业：探索单层过渡金属二硫化物中自旋极化激子的激子-激子相关性和相变

• 批准号: 2142703
• 负责人: Xiao-Xiao Zhang
• 金额: $ 77.92万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2142703&HistoricalAwards=false
• 关键词: CAREER; Probing; exciton; correlations; phase

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Non-technical abstract When light is absorbed by a solid, it can create a transient excitation quasiparticle, the so-called exciton, which carries information from both the light and the matter. Understanding excitonic interactions are crucial for the future design of quantum devices with contact-free, all-optical control and sensing. This project investigates the quantum correlations between excitons in an atomically-thin two-dimensional crystal with exceptionally strong light-matter interactions. The unique optical and electronic properties of the two-dimensional crystal promise the realization of quantum correlation well above the liquid helium temperature. The research results will establish new platform systems to achieve on-chip operation and control of coherence for future quantum technology developments. Integrated with the research, the project aims to promote the participation of women in STEM and train the next-generation STEM workforce through interdisciplinary research projects and tasks. A series of career support seminars for women in STEM will be organized at the University of Florida. In addition, optics science demonstration stations will be developed for display in a local museum to increase STEM awareness in a younger generation.This project is jointly funded by the Condensed Matter Physics (CMP) and the Electronic and Photonic Materials (EPM) programs of the Division of Materials Research (DMR).Technical abstract An exciton is a bound electron-hole pair that can be considered as a Boson, often created through optical excitations in semiconductors. Beyond the dilute exciton gas limit, exciton-exciton correlation forms, and the possibility of achieving quantum degeneracy of exciton liquid and condensate phases have attracted great attention for decades. The recent advent of two-dimensional (2D) semiconductors of transition metal dichalcogenides provides a completely new paradigm for exciton physics, where excitons have anomalously strong binding energy and enable all-optical control of the spin and valley degrees of freedom. This project aims to investigate the nonlinear exciton interactions and seek experimental signatures of exciton complex correlations in tungsten-based monolayer transition metal dichalcogenides. In particular, this research will focus on spin-polarized excitonic states, which have long lifetimes and support a high exciton density. Both the classical regime and the possible quantum degeneracy of 2D excitons will be investigated through a combination of ultrafast optical spectroscopies and optoelectronic probes. The outcome will inform our understanding of excitonic many-body interactions in 2D and lay the foundation for realizing macroscopic coherence in compact 2D devices. Investigation of these spin-polarized excitons will also elucidate how the spin polarization of bosons affects the formation of correlation and further macroscopic coherence.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.

该奖项是根据2021年《美国救援计划法》（公法117-2）全部或部分资助的。非技术摘要当光被固体吸收时，它可以产生瞬态激发准粒子，即所谓的激子，该弹性量均来自光和物质。了解激子相互作用对于通过无接触，全光控制和感应的量子设备的未来设计至关重要。该项目研究了具有异常强的光 - 晶体相互作用的原子较薄的二维晶体中激子之间的量子相关性。二维晶体的独特光学和电子特性有望实现量高于液体氦气温度的量子相关性。研究结果将建立新的平台系统，以实现未来量子技术开发的连贯性运行和控制。该项目与研究融为一体，旨在促进妇女参与STEM，并通过跨学科研究项目和任务来培训下一代STEM劳动力。 STEM女性的一系列职业支持研讨会将在佛罗里达大学组织。 In addition, optics science demonstration stations will be developed for display in a local museum to increase STEM awareness in a younger generation.This project is jointly funded by the Condensed Matter Physics (CMP) and the Electronic and Photonic Materials (EPM) programs of the Division of Materials Research (DMR).Technical abstract An exciton is a bound electron-hole pair that can be considered as a Boson, often created through optical excitations in半导体。除了稀释的激情气体限制，激子 - 外激体相关形式以及实现激子液体和冷凝水阶段量子退化的可能性已引起了数十年的极大关注。最近的二维（2D）半导体的出现，过渡金属二进制基因源为激子物理学提供了一个全新的范式，其中激素具有异常强的结合能，并启用了自旋和山谷自由度的全光控制。该项目旨在研究非线性激子相互作用，并寻求基于钨的单层过渡金属二核苷中激子复合物相关性的实验特征。特别是，这项研究将集中于自旋极化的激子状态，后者的寿命很长，并支持高激子密度。 2D激子的经典状态和可能的量子退化都将通过超快光谱和光电探针的组合进行研究。结果将为我们对2D中的激子多体相互作用的理解提供信息，并为实现紧凑型2D设备中的宏观连贯性奠定了基础。对这些自旋偏振激子的研究还将阐明玻色子的自旋极化如何影响相关的形成和进一步的宏观连贯性。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来通过评估来支持的。