Two Dimensional Performance with Three Dimensional Capacity: Engineering the Thermal Properties of Graphene

本计画的目的是研究旋转角度对扭曲双层石墨烯导热系数的影响。实验和理论证据清楚地表明，扭曲双层石墨烯中各个层的电子态是解耦的。扭转角对声子色散的影响仍然是一个悬而未决的问题，而扭转角对面内热输运的影响还有待研究。这些问题是密切相关的，因为热是由声子携带的。 如果扭曲石墨烯层中的声子耦合被抑制，则多层扭曲石墨烯膜将具有并联作用的单个2D层的增强的热导率，从而允许传递非常大的热通量。该程序的智力价值在于创建确定双层石墨烯的扭曲角与热导率的关系的基础知识。通过使用错位堆叠来保持块状材料中石墨烯的2D特性的可能性是一个变革性的概念，给我们两全其美的机会。2D的增强性能与3D的容量相结合。该项目的更广泛影响包括石墨烯在热管理方面的新应用。它有可能提高美国的技术竞争力。它将增加妇女和代表性不足的少数民族的参与，并有助于本科和研究生干教育在加州大学滨江，这是少数服务机构与最大的西班牙裔学生人口之间的所有加州大学校园。该项目由电气，通信和网络系统（ECCS）部门的电子，光子学和磁器件计划（EPMD）以及材料研究（DMR）部门的电子和光子材料计划（EMPs）共同资助。

The objective of this program is to investigate the effect of rotation angle on the thermal conductivity of twisted bilayer graphene. The experimental and theoretical evidence is clear that the electronic states of the individual layers in twisted bilayer graphene are decoupled. The effect of the twist angle on the phonon dispersion is still an open question, and the effect of twist angle on the in-plane thermal transport has yet to be studied. These questions are intimately related since the heat is carried by the phonons. If the phonon coupling in twisted graphene layers were suppressed, then the multi-layer twisted graphene films would have enhanced thermal conductivity of single 2D layers acting in parallel, thus allowing for transfer of extraordinary large heat fluxes. The intellectual merit of this program is in creating fundamental knowledge determining the relation of twist angle to the thermal conductivity of bilayer graphene. The possibility of maintaining 2D properties of graphene in bulk materials through the use of misoriented stacking is a transformational concept giving us the best of both worlds ? the enhanced performance of 2D combined with the capacity of 3D.The broader impact the project includes new applications of graphene for thermal management. It has the potential to increase the US technological competitiveness. It will increase the participation of women and underrepresented minorities and contribute to undergraduate and graduate STEM education at UC Riverside, which is the minority serving institution with the largest Hispanic student population among all UC campuses. This project is jointly funded by the Electronics, Photonics, and Magnetic Devices Program (EPMD) in the Division of Electrical, Communications and Cyber Systems (ECCS) and by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR).