CAREER: Chiral Phenomena of Excited States in Spintronics

手性是自然界中普遍存在的一种现象，从基本粒子到化学和生物分子。大多数手征现象的研究依赖于手性的静态观点，即一个物体是否可以叠加到它的镜像上。事实上，手性的概念可以扩展到移动的物体：例如，Rattleback是一种只在首选方向上旋转的旋转陀螺。在凝聚态系统中，动力学手性可以导致各种有趣的现象和应用。在这里，研究小组专注于原子薄范德华材料中结构、电子、磁动力学之间的手性相互作用。该研究项目结合了先进的光谱学和建模技术来研究手性相互作用产生的光学和传输特性。这些性质有望产生圆偏振光，实现电子的单向动力学，可应用于新型光电子器件。这一职业计划的研究方面与广泛的教育和外联活动机会相结合。研究生和本科生不仅在首席研究员实验室接受材料科学、纳米制造和激光物理方面的培训，而且还利用国家实验室设施参与光谱学实验。此外，研究团队还积极邀请K-12学生和普通公众通过开发新的STEM演示和游戏来传达手性和对称之美的概念。技术摘要：在凝聚态系统中，动态手性的概念以各种有趣的性质扩展了自旋电子学的范围。在这个过程中，手性在不同自由度之间的能量和角动量传递中起着至关重要的作用。本项目的目标是研究二维材料和范德华异质结构中磁、声子和光子激发之间的手性相互作用所产生的新颖磁光效应和非互易输运性质。研究小组正在寻求解决自旋电子学中几个最新和最相关的科学问题：1)如何相干地激发手性声子并提升非手性材料中的手性声子简并？2)手性如何在二维极限中调节磁振子-声子耦合？3)如何在声子二极管器件中实现非互易信号操作的手性相互作用？使用了国内机构和国家实验室的一系列最先进的实验技术，如非线性光学、螺旋度分辨拉曼散射和铁磁共振光谱来执行研究任务。这项研究项目揭示了更广泛的材料类别中的紧急手性现象，并将自旋电子学推进到与量子信息科学的跨学科制度。该项目由材料研究部的凝聚态物理计划(CMP)和既定的刺激竞争研究计划(EPSCoR)联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Abstract: Chirality is a ubiquitous phenomenon in nature, ranging from elementary particles to chemistry and biomolecules. Most studied chiral phenomena rely on a static view of chirality, that is, whether an object can be superimposed on its mirror image. In fact, the concept of chirality can be extended to moving objects: rattleback, for example, is a spinning top that only rotates in a preferred direction. In condensed matter systems, dynamic chirality can lead to a variety of interesting phenomena and applications. Here, the research team focuses on the chiral interactions between structural, electronic, magnetic dynamics in atomically thin van der Waals materials. The research project brings together advanced spectroscopy and modeling techniques to investigate the optical and transport properties emerged from chiral interactions. These properties hold the promise of producing circularly polarized light and realizing unidirectional dynamics of electrons, which can be implemented into novel opto-electronic device applications. The research aspects of this CAREER plan are integrated with extensive opportunities for education and outreach activities. Graduate and undergraduate students are not only trained in materials science, nanofabrication, and laser physics in the principal investigator’s lab, but also involved in spectroscopy experiments using national lab facilities. Also, the research team actively engage the K-12 students and general public to convey the concept of chirality and the beauty of symmetry by developing new STEM demos and games. Technical Abstract: In condensed matter systems, the concept of dynamic chirality expands the scope of spintronics with various intriguing properties. In this process, chirality plays a critical role in the energy and angular momentum transfer among different degrees of freedom. The objective of this project is to study novel magneto-optical effects and nonreciprocal transport properties that emerge from chiral interactions between magnetic, phononic, and photonic excitations in two-dimensional materials and van der Waals heterostructures. The research team are seeking to address several most current and relevant scientific problems in spintronics: 1) How to coherently excite chiral phonons and lift chiral phonon degeneracy in an achiral material? 2) How does chirality mediate the magnon-phonon coupling in the two-dimensional limit? and 3) How to implement chiral interactions in a phonon diode device for nonreciprocal signal operation? A battery of state-of-the-art experimental techniques at the home institution and the national laboratories such as nonlinear optics, helicity-resolved Raman scattering, and ferromagnetic resonance spectroscopy are employed to carry out the research tasks. This research project shed light on the emergent chiral phenomena in a broader class of materials and advance spintronics towards the interdisciplinary regime with quantum information science.This project is jointly funded by the Condensed Matter Physics Program (CMP) in the Division of Materials Research and by the Established Program to Stimulate Competitive Research (EPSCoR).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.