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Nonequilibrium Control of Magnetism and Topology Through Selective Phonon Excitations

通过选择性声子激发对磁性和拓扑的非平衡控制

基本信息

批准号：
2114825
负责人：
Gregory Fiete
金额：
$ 37万
依托单位：
Northeastern University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114825&HistoricalAwards=false
关键词：
Nonequilibrium Control Magnetism Topology Through

项目摘要

NONTECHNICAL SUMMARYThis award supports research and educational activities with an aim to understand and predict novel regimes of matter in quantum materials. The PI will focus his theoretical research on materials driven out-of-equilibrium from illumination by lasers of different light frequencies and polarization. The high purity light of a laser, which is very nearly of a single frequency in contrast to light from the sun or a light bulb, allows one to selectively deposit energy into the different (e.g. lattice, electronic, magnetic) degrees of freedom of a solid material. Because these different degrees of freedom interact with one another, energy deposited in one will ultimately be distributed among the others after some time, but at intermediate times interesting non-equilibrium phenomena can result. The goal of this project is to uncover interesting electrical and magnetic possibilities theoretically, and help guide experimental groups in their realization in the laboratory. Ultimately, this research may enable new quantum technologies based on light control of matter, including sensing, computing, and communication applications.In addition, this project will support the training of graduate and undergraduate students through direct involvement with the PI in the research described. The PI will continue to deliver a wide range of public lectures with a focus on pre-college students from historically underrepresented backgrounds who have had limited exposure to theoretical physics and/or quantum sciences. Some of these lectures will be delivered through Northeastern University’s Center for STEM Education. The PI will participate in the Building Bridges Program at Northeastern, an interactive day to introduce prospective college students to the sciences and engineering, and the Young Scholars program at Northeastern, a 6-week intensive summer program where rising high-school seniors work on cutting edge research problems and receive mentoring from faculty and university students.TECHNICAL SUMMARYThis award supports research and educational activities with an aim to understand and predict novel regimes of matter in quantum materials out-of-equilibrium. The PI will theoretically study the influence of laser-induced lattice changes on the electronic states of correlated electronic materials with strong spin-orbit coupling. The project will substantially extend equilibrium studies of systems with both strong spin-orbit coupling and electronic correlations to the non-equilibrium regime. By directly targeting selected phonon modes in a material with light, heating effects can be minimized, and coherent electronic and magnetic responses generated. Topological transitions, including higher order topological states, in the electronic and magnon band structures and redistribution of Berry curvature in the Brillouin zone will be a focus, as well as phase transitions/phase stabilization of unusual charge-ordered, magnetically-ordered, and superconducting states. Of particular interest will be nonlinear effects that may be induced in the materials through intense light. Nonlinear phononic studies and effects beyond the linear response regime (such as higher harmonic generation) will be studied as a means to drive and detect novel physical regimes and excitations created by intense, low-frequency light. The PI will use complementary theoretical methods that start from both the strong coupling limit and the weak coupling regime to explore the link between laser-induced lattice changes and electronic/magnetic property changes. Numerical and analytical approaches, including model Hamiltonian and first-principles studies, along with symmetry arguments will be employed.In addition, this project will support the training of graduate and undergraduate students through direct involvement with the PI in the research described. The PI will continue to deliver a wide range of public lectures with a focus on pre-college students from historically underrepresented backgrounds who have had limited exposure to theoretical physics and/or quantum sciences. Some of these lectures will be delivered through Northeastern University’s Center for STEM Education. The PI will participate in the Building Bridges Program at Northeastern, an interactive day to introduce prospective college students to the sciences and engineering, and the Young Scholars program at Northeastern, a six-week intensive summer program where rising high-school seniors work on cutting edge research problems and receive mentoring from faculty and university students.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.

该奖项支持研究和教育活动，旨在理解和预测量子材料中物质的新机制。PI将专注于他的理论研究材料驱动从不同的光频率和偏振的激光照射的平衡。与来自太阳或灯泡的光相比，激光器的高纯度光非常接近单一频率，这允许人们选择性地将能量存款到固体材料的不同（例如晶格、电子、磁性）自由度中。由于这些不同的自由度相互作用，储存在一个自由度中的能量最终会在一段时间后分布在其他自由度中，但在中间时间，可能会导致有趣的非平衡现象。该项目的目标是从理论上揭示有趣的电磁可能性，并帮助指导实验组在实验室中实现。最终，这项研究可能使基于光控制物质的新量子技术成为可能，包括传感、计算和通信应用。此外，该项目将通过直接参与PI所述研究来支持研究生和本科生的培训。PI将继续提供广泛的公开讲座，重点是来自历史上代表性不足的背景的大学预科学生，他们对理论物理和/或量子科学的接触有限。其中一些讲座将通过东北大学的STEM教育中心提供。PI将参加东北大学的建桥计划，这是一个向未来的大学生介绍科学和工程的互动日，以及东北大学的青年学者计划，一个为期6周的暑期强化课程，高年级学生致力于前沿研究问题，并接受教师和大学生的指导。技术总结该奖项支持研究和教育活动，旨在理解和预测量子材料中物质的新机制。PI将从理论上研究激光诱导晶格变化对强自旋轨道耦合关联电子材料电子态的影响。该项目将把对具有强自旋轨道耦合和电子关联的系统的平衡研究大大扩展到非平衡状态。通过用光直接瞄准材料中选定的声子模式，可以最小化加热效应，并产生相干的电子和磁响应。拓扑转变，包括更高阶的拓扑状态，在电子和磁振子带结构和重新分布的布里渊区的Berry曲率将是一个焦点，以及相变/相位稳定的不寻常的电荷有序，磁有序，和超导状态。特别令人感兴趣的将是通过强光在材料中可能引起的非线性效应。非线性声子研究和超出线性响应机制（如高次谐波产生）的影响将被研究作为一种手段来驱动和检测新的物理机制和激发产生的强烈，低频光。PI将使用互补的理论方法，从强耦合极限和弱耦合区开始，探索激光诱导晶格变化和电子/磁性变化之间的联系。数值和分析的方法，包括模型哈密顿和第一原理研究，沿着与对称性参数将采用。此外，该项目将支持研究生和本科生的培训，通过直接参与PI在所描述的研究。PI将继续提供广泛的公开讲座，重点是来自历史上代表性不足的背景的大学预科学生，他们对理论物理和/或量子科学的接触有限。其中一些讲座将通过东北大学的STEM教育中心提供。PI将参加东北大学的建桥计划，这是一个向未来的大学生介绍科学和工程的互动日，以及东北大学的青年学者计划，一个为期六周的暑期强化课程，高年级学生致力于前沿研究问题，并接受教师和大学生的指导。该奖项反映了NSF的法定使命，并被认为值得支持通过使用基金会的知识价值和更广泛的影响审查标准进行评估。