Shi Wenhao, Guo Yufeng, Zhang Zhuhua, Guo Wanlin
State Key Laboratory of Mechanics and Control of Mechanical Structures and MOE Key Laboratory for Intelligent Nano Materials and Devices, College of Aerospace Engineering , Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China.
J Phys Chem Lett. 2018 Dec 6;9(23):6841-6846. doi: 10.1021/acs.jpclett.8b03325. Epub 2018 Nov 20.
Flexoelectricity, the coupling effect of the strain gradient and charge polarization, is an important route to tune electronic properties of low-dimensional materials. Here our extensive first-principles calculations reveal that structural wrinkling and corrugation will cause significant flexoelectricity in transition metal dichalcogenide (TMD) monolayers. The flexoelectricity is induced by the strain gradients created along the finite thickness of the wrinkled TMD monolayers and becomes more dominant in determining out-of-plane polarizations with decreasing wavelengths of the TMD wrinkles. According to the first-principles calculations and whole structural symmetry, a theoretical model is developed to describe the total out-of-plane polarizations and flexoelectric effect of the wrinkled TMD monolayers. The unveiled flexoelectricity in monolayer TMDs highlights a potential for their application in energy conversion devices.
挠曲电效应，即应变梯度与电荷极化的耦合效应，是调控低维材料电子性质的重要途径。在此，我们广泛的第一性原理计算表明，结构褶皱和波纹会在过渡金属二硫属化物（TMD）单层中引起显著的挠曲电效应。挠曲电效应由沿褶皱TMD单层有限厚度产生的应变梯度诱导产生，并且随着TMD褶皱波长的减小，在决定面外极化方面变得更加显著。根据第一性原理计算和整体结构对称性，建立了一个理论模型来描述褶皱TMD单层的总面外极化和挠曲电效应。在单层TMD中揭示的挠曲电效应突出了其在能量转换器件中的应用潜力。
