We investigate electromechanical properties of two-dimensional MoS2 monolayers in the 1H, 1T, and 1T′ structures as a function of charge doping by using density functional theory. We find isotropic elastic moduli in the 1H and 1T structures, while the 1T′ structure exhibits an anisotropic elastic modulus. Moreover, the 1T structure is shown to have a negative Poisson's ratio, while Poisson's ratios of the 1H and 1T′ are positive. By charge doping, the monolayer MoS2 shows a reversibly strain and work density per cycle ranging from -0.68% to 2.67% and from 4.4 to 36.9 MJ/m3, respectively, making them suitable for applications in electromechanical actuators. Stress generated is also examined in this work and we find that 1T and 1T′ MoS2 monolayers relatively have better performance than 1H MoS2 monolayer. We argue that such excellent electromechanical performance originate from the electrical conductivity of the metallic 1T and semimetallic 1T′ structures high Young's modulus of about 150−200 GPa.
@article{arxiv.1711.00188,
title = {Two-dimensional MoS$_2$ electromechanical actuators},
author = {Nguyen T. Hung and Ahmad R. T. Nugraha and Riichiro Saito},
journal= {arXiv preprint arXiv:1711.00188},
year = {2018}
}