CAREER: Acoustic Phonons in 2D Materials

非技术描述本项目研究声波如何使用基于激光的技术在一种新的原子薄的二维(2D)材料中运动，如何使用化学来改变这种运动，以及如何利用这一知识来提高技术。固体材料中的声波以“声子”的形式运动，声子的作用就像声音的单个粒子。声子可以携带热量并影响携带电流的电子，从而影响材料设备和应用。这个项目将进一步加深对2D材料声子性质的理解，填补我们基础知识中的一个重大空白。这项工作为科学和工程领域的职业培养本科生和研究生。教育和更广泛的外展目标包括：(I)开发一个公开可用的在线布里渊光谱数据库，(Ii)发起为期一天的年度Science Impact-East会议，向普罗维登斯、国际扶轮地区未得到充分服务的高中生和教师介绍科学和技术职业，以及(Iii)招募未被充分代表的少数民族、女高中生和本科生参与科学研究。该奖项支持一个项目，以了解二维(2D)硫化物(S、硒、碲)和氧化物材料的声学性质，以符合我们目前对其电子性质的理解。布里渊激光光散射将被用来映射内部合成的2D材料的声学声子色散关系。将引入新的插层化学方法，通过化学调节层与层之间的耦合来系统地控制层间声子行为。缺陷(空洞、空位和晶界)将被用化学方法设计成2D材料，以研究它们对基本声子行为的影响。这项工作为完全理解和控制二维硫化物和氧化物材料中的声子奠定了基础，并将指导对二维材料未来应用中的力学行为、热传输和器件故障的理解。

Non-Technical Description This project studies how sound waves move in a new class of atomically-thin, two-dimensional (2D) materials using a laser-based technique, how to alter this motion using chemistry, and how to use this knowledge to enhance technologies. Sound waves in solid materials move in the form of "phonons," which act like individual particles of sound. Phonons can carry heat and affect electrons that carry electrical currents, impacting material devices and application. This project will further the understanding of the phonon properties of 2D materials, filling a major gap in our fundamental knowledge. This work trains undergraduate and graduate students for careers in science and engineering. Educational and broader outreach goals include: (i) development of a publicly available online Brillouin spectroscopy database, (ii) initiation of an annual one-day Sciimpact-East conference to introduce underserved high school students and teachers in the Providence, RI area to careers in science and technology, and (iii) recruitment of under-represented minority and female high school students and undergraduates to participate in scientific research.Technical Description This award supports a project to understand the phononic properties of two-dimensional (2D) chalcogenide (S, Se, Te) and oxide materials to match our current understanding of their electronic properties. Brillouin laser light scattering will be used to map the acoustic phonon dispersion relations of 2D materials, synthesized in-house. Novel intercalation chemistries will be introduced toward systematically controlling the interlayer phonon behavior by chemically modulating the layer-to-layer coupling. Defects (voids, vacancies, and grain boundaries) will be engineered into 2D materials using chemical methods for investigating their impact on fundamental phonon behavior. This effort lays the foundation for the complete understanding and the chemical control of phonons in 2D chalcogenide and oxide materials and will guide understanding of mechanical behavior, heat transport and device failure in future applications of 2D materials.