单原子层材料的压电效应研究

项目名称： 单原子层材料的压电效应研究

项目编号： No.11502308

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 王云华

作者单位： 中山大学

项目金额： 22万元

中文摘要： 压电材料因其能直接实现力电信号(机械能与电能)之间的相互转换被广泛用作传感器、致动器和能量收集器，因此研究这种力电信号之间的转换效应，即压电效应，具有及其重要的意义。单原子层材料 (二维材料)，是指仅仅具有一个原子层厚度的材料，它因其特殊的二维膜状结构而拥有大的弹性变形范围。这种大范围弹性变形和其电学性能的组合使它呈现出丰富的力电耦合效应。因此，研究单原子层材料的压电效应是当前微纳力学、纳机电和智能传感等领域的最前沿热点。最新的实验表明，不具有晶格反演对称中心的单原子层二硫化钼材料拥有强的线性压电效应，以及具有晶格反演对称中心的石墨烯拥有新型的能带压电效应和挠曲电效应，这些现象背后的物理尚不知晓。本项目结合实验致力于建构一套能完善地描述单原子层材料中所有这些压电效应的物理理论。

中文关键词： 压电效应；挠曲电效应；能带压电效应；二维材料；石墨烯

英文摘要： Piezoelectric materials have been broadly used as sensors, actuators and energy harvesters, due to the direct conversion between mechanical signals and electric signals (mechanical energy and electrical energy). As a result, it is of prime importance to investigate the mechanical- electric conversion effect, i.e., the piezoelectric effect. Material with a single-atomic-layer, i.e., two-dimensional material, can withstand enormous elastic deformation due to its membrane-like structure. The interplay between the large elastic deformation and electronic properties induces fantastic electromechanical coupling effects. Consequently, the piezoelectric effect in two-dimensional material has aroused widespread concern in Nano/micro-Mechanics, Nanoelectromechanical system and smart sensors. Current experiments show that single layer of molybdenum disulphide without the inversion symmetry of crystal lattice has strong piezoelectricity and graphene with the inversion symmetry of the lattice structure has unprecedented band-piezoelectric effect and the flexoelectricity. However, the physical mechanism of these piezoelectric effects in the two-dimensional materials is not clear. The aim of this project is to construct a complete physical theory describing all these piezoelectric effects.

英文关键词： piezoelectric effect;flexoelectric effect ;band-piezoelectric effect;two-dimensional material;graphene