Edge Effect On Flexoelectronic Properties Of Janus Mosse Nanoribbons: A First-Principles Study

The edge elasticity and its effect on flexoelectric response of the Janus MoSSe nanoribbons are systematically explored by means of density functional theory based first-principles calculations. We report edge stresses, edge elastic moduli, and structural deformations of the Janus MoSSe nanoribbons with various widths. It is shown that both armchair and zigzag terminated edges of the MoSSe nanoribbons are essentially subjected to tension, due to the existence of the edge stresses. The magnitude of average zigzag edge stresses is much larger than that of the average armchair ones. Furthermore, our results show that both misfit strain induced by asymmetric chalcogen atomic layers, and the edge stresses cause the spontaneous bending deformation of such Janus nanoribbons. More importantly, flexoelectronic properties of semiconducting armchair MoSSe nanoribbons are carefully evaluated and compared with those of armchair MoS2 and MoSTe nanoribbons. In particular, it is found that the out-of-plane flexoelectronic coefficients strongly depend on their widths. Additionally, the flexoelectric response resulting from spontaneous bending is weaker than that from the opposite one. The implicit mechanisms on deformations and flexoelectronic properties of such Janus nanoribbons have been carefully explored. The results in this work provide useful insights into their potential applications in nanoscale electromechanical systems.