CDS&E: Ab Initio Ultrafast Dynamics of Spin, Valley and Charge in Quantum Materials

CDS

• 批准号: 1956015
• 负责人: Yuan Ping
• 金额: $ 49.46万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1956015&HistoricalAwards=false
• 关键词: CDS& Ab; Initio; Ultrafast; Dynamics

This grant is being funded by the Condensed-Matter and Materials Theory program in the Division of Materials Research and by the Chemical Theory, Models, and Computational Methods program in the Division of Chemistry.Nontechnical SummaryThe promise of quantum computers to perform calculations beyond the reach of any current or conceivable non-quantum computer has made them one of the nation's highest research priorities. This award supports computational research and education on the motion of electrons in quantum materials. Several recently-discovered materials exhibit the potential to store quantum information in individual electrons that may hold the key to the next generation of quantum computers and quantum communication. Realizing the full potential of these materials requires precise understanding of how long quantum information can be stored in electron spins and how it disappears eventually by interacting with the vibrations of atoms in the material.The investigators will develop a computational methodology to simulate quantum electron motion on large supercomputers. They will use this technique to predict how electron spin changes over times ranging from femtoseconds to microseconds in several promising materials, such as lead halide perovskites, containing heavy atoms that couple spin to the movement of electrons. Electrons in transition-metal dichalcogenides, another alternative for storing quantum information, can be found in multiple so-called "valleys;" the investigators will also study how electron valley and electron spin couple. For each of these materials, they will simulate the interaction of these quantum states with extremely short laser pulses to interpret experimental measurements of spin and valley dynamics.This award will also support the team's effort in increasing participation and representation of women in STEM disciplines, especially in the physical sciences. By integrating simulations into intuitive visualizations using augmented reality, they will make electron dynamics understandable to undergraduate and high school students. Finally, this project will strengthen the research infrastructure at UCSC, a Hispanic Serving Institution.Technical summaryThe goal of this research project is to predict quantitatively quantum dynamics of electrons with spin, valley, or other internal degrees of freedom, entirely from first principles. The research team will develop a novel computational methodology and associated massively-parallel open-source software rapidly to evolve density matrices of quantum materials in a Lindbladian formulation, with ab initio treatment of electron-electron, electron-phonon, and electron-photon interactions. This will facilitate calculation of both coherent dynamics and dephasing of spin or valley polarization, along with their experimental signatures in ultrafast spectroscopy. Using this technique, they will investigate spin dynamics in systems with strong spin-orbit coupling and Rashba splitting such as lead halide perovskites and ferroelectric oxides, and valley dynamics in layered transition metal dichalcogenides. This fundamentally new predictive capability will facilitate quantitative analysis of ultrafast optical and free-electron laser measurements with linear and circular polarization, and accurate predictions of spin relaxation of quantum materials. This will be critical for the design and discovery of new material platforms for spintronics, valleytronics and quantum information.The proposed work will arm the materials research community with first-principles quantum dynamics methods in open-source software. These will include a hierarchy of methods that keep track of different levels of coherence, with corresponding computational requirements ranging from a small computer cluster to future exascale supercomputers. It will thereby deliver a key computational technique necessary for predicting coherent and incoherent ultrafast dynamics in quantum materials, extending significantly beyond the capabilities of existing first-principles methods. The work funded in this project responds directly to one of NSF's 10 Big Ideas, the Quantum Leap, by facilitating quantitative simulation of spin relaxation and carrier dynamics critical for quantum information science. The educational activities associated with this project aim to increase participation and representation of women in STEM disciplines, especially in the physical sciences. It will expand the reach of materials simulations to K-12 education through the platform of augmented reality. This project will also strengthen the research infrastructure at UCSC, a Hispanic Serving Institution.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.

这笔赠款由材料研究部的凝聚态和材料理论项目以及化学部的化学理论、模型和计算方法项目资助。非技术摘要量子计算机有望执行超出范围的计算任何当前或可想象的非量子计算机的性能使其成为美国最高的研究重点之一。 该奖项支持量子材料中电子运动的计算研究和教育。 最近发现的几种材料表现出在单个电子中存储量子信息的潜力，这可能是下一代量子计算机和量子通信的关键。 要充分发挥这些材料的潜力，需要精确了解量子信息可以在电子自旋中存储多长时间，以及量子信息如何通过与材料中原子的振动相互作用而最终消失。研究人员将开发一种计算方法来模拟量子电子运动大型超级计算机。 他们将使用这项技术来预测几种有前途的材料中电子自旋如何随飞秒到微秒的时间变化，例如卤化铅钙钛矿，含有将自旋与电子运动耦合的重原子。 过渡金属二硫化物中的电子是存储量子信息的另一种选择，可以在多个所谓的“谷”中找到；研究人员还将研究电子谷和电子自旋如何耦合。 对于每种材料，他们将模拟这些量子态与极短激光脉冲的相互作用，以解释自旋和谷动力学的实验测量结果。该奖项还将支持该团队为提高女性在 STEM 学科的参与和代表性所做的努力，特别是在物理科学中。通过使用增强现实将模拟集成到直观的可视化中，他们将使本科生和高中生能够理解电子动力学。最后，该项目将加强 UCSC（西班牙裔服务机构）的研究基础设施。技术摘要该研究项目的目标是完全根据第一原理定量预测具有自旋、谷或其他内部自由度的电子的量子动力学。研究团队将开发一种新颖的计算方法和相关的大规模并行开源软件，以林布拉德公式快速演化量子材料的密度矩阵，并从头开始处理电子-电子、电子-声子和电子-光子相互作用。这将有助于计算相干动力学和自旋或谷偏振的相移，以及它们在超快光谱中的实验特征。利用这项技术，他们将研究具有强自旋轨道耦合和 Rashba 分裂的系统中的自旋动力学，例如卤化铅钙钛矿和铁电氧化物，以及层状过渡金属二硫属化物中的谷动力学。这种全新的预测能力将有助于对线性和圆偏振的超快光学和自由电子激光测量进行定量分析，并准确预测量子材料的自旋弛豫。这对于自旋电子学、谷电子学和量子信息的新材料平台的设计和发现至关重要。拟议的工作将为材料研究界提供开源软件中的第一原理量子动力学方法。这些将包括跟踪不同级别的一致性的方法层次结构，以及从小型计算机集群到未来百亿亿级超级计算机的相应计算要求。因此，它将提供预测量子材料中相干和非相干超快动力学所必需的关键计算技术，大大超出现有第一原理方法的能力。该项目资助的工作通过促进对量子信息科学至关重要的自旋弛豫和载流子动力学的定量模拟，直接响应了 NSF 的 10 大想法之一“量子飞跃”。与该项目相关的教育活动旨在提高女性在 STEM 学科（尤其是物理科学领域）的参与度和代表性。它将通过增强现实平台将材料模拟的范围扩大到 K-12 教育。该项目还将加强西班牙裔服务机构 UCSC 的研究基础设施。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。

项目成果

Electric fields and substrates dramatically accelerate spin relaxation in graphene

电场和基底显着加速石墨烯中的自旋弛豫

• DOI: 10.1103/physrevb.105.115122
• 发表时间: 2022-03
• 期刊: Physical review
• 作者: Habib, Adela;Xu, Junqing;Ping, Yuan;Sundararaman, Ravishankar
• 通讯作者: Sundararaman, Ravishankar

Ab initio ultrafast spin dynamics in solids

固体中从头算超快自旋动力学

• DOI: 10.1103/physrevb.104.184418
• 发表时间: 2021-11
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Xu, Junqing;Habib, Adela;Sundararaman, Ravishankar;Ping, Yuan
• 通讯作者: Ping, Yuan

Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics

从第一性原理密度矩阵动力学研究硅烯和锗烯中的巨自旋寿命各向异性和自旋谷锁定

• DOI: 10.1021/acs.nanolett.1c03345
• 发表时间: 2021-11
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Xu, Junqing;Takenaka, Hiroyuki;Habib, Adela;Sundararaman, Ravishankar;Ping, Yuan
• 通讯作者: Ping, Yuan

Plasmonic hot carriers scratch the surface

等离激元热载流子划伤表面

• DOI: 10.1016/j.trechm.2021.08.006
• 发表时间: 2021-09-02
• 期刊: Trends in Chemistry
• 影响因子: 15.7
• 作者: Sushant Kumar;A. Habib;R. Sundararaman
• 通讯作者: R. Sundararaman