电场诱导下二维纳米材料超润滑现象与机理研究

Superlubricity has features of super-low friction coefficient and ultra-low wear rate, and it is a fundamental way to eliminate energy consumption and mechanical wear. Structural superlubricity has even lower friction and wear. However, current research still has such limitations as small contacting area, unclear mechanisms and few potential materials, and most of the experiments are conducted only under highly vacuum environments. To deal with the problems mentioned above, a new method to realize structural superlubricity by applying electric field on the friction interface is proposed, and its mechanism is also attractive to deeply understand. The electronic properties on the surface of two-dimensional materials is precisely controlled by adjusting an external electric field, in order to smooth electric potential, decrease the friction coefficient and realize superlubric status. Furthermore, the superlubricity of two-dimensional materials under different circumstances such as atmosphere, temperature and vacuum are still investigated, so as to understand the relationships between superlubricity and complex environments with the electric field intensity, interfacial atomic structure, surface electronic properties and other related factors being different. We try our best to achieve pioneering results on discovering new superlubric phenomenon and clarifying the mechanism behind them. This research is helpful and vital to promote the future of superlubricity and widening its applications.

超润滑拥有摩擦系数低和磨损率小的特点，是降低一次性能源消耗和机械设备磨损的根本途径。其中结构超润滑是晶体之间以非公度形式接触产生的超润滑，具有极低的摩擦和磨损。目前国内外结构超润滑的研究面临使用环境受限,摩擦接触面积较小，形成机理不明晰和材料种类少等几个共性问题。针对上述问题，项目组提出采用外加电场诱导实现结构超润滑的新方法，并开展其机理研究。通过外加电场精确调制二维纳米材料表面电子学性质，平滑表面电势垒，降低界面摩擦系数并实现结构超润滑。在此基础上开展气氛、温度和真空度等多种可控外部环境下二维材料超润滑研究，掌握多种复杂环境下的运动规律，并阐明外加电场、界面原子排列、表面电子学性质等多因素对结构超润滑的作用规律。力求在超润滑新现象发现和机理揭示两方面取得前沿性的学术成果，该研究的顺利实施对推动超润滑发展，拓展其应用领域有重要的帮助和支撑作用。

以石墨烯、二硫化钼为代表的二维层状材料由于其弱的层间作用力和易获得原子级平滑表面而作为超滑研究的重要材料，但是其超滑的机理尚不明确。本工作从层间作用力、应力应变、材料层厚、摩擦速度、电子束注入以及电场诱导等方面调制摩擦副表面电子学性质，从而开展材料电子学性质对超滑机理的研究，找到调控结构超滑的新方法。通过基于声子振动的低波数拉曼与一维双原子链模型，研究了层间摩擦力与其界面堆垛结构的关联规律，获得了基于声电子行为的二维材料界面性质检测技术。通过应力应变、晶格结构调制、电子束注入、摩擦速度调制、电场诱导等方法改变了摩擦副电子学性质，从而调控微观摩擦能量耗散过程中的声子激发、激子激发/耗散等过程，改变了表面摩擦特性。通过揭示材料电子学性质与摩擦能量耗散的关联机制，获得了摩擦调控的新方法，同时，推动了原子尺度摩擦能量耗散的机理研究，为摩擦能量耗散调制提供了新的方向。