A MOLECULAR DYNAMICS STUDY ON THE PIEZOELECTRIC PROPERTIES OF BULK ZnS AND NANOBELTS

A number of researchers have developed interatomic potentials for ZnS. The choice and reliability of a particular empirical ZnS potential is highly dependent on the application that the molecular mechanic simulation aims for, and therefore each of these potentials is designed to reproduce some specific ZnS properties. Therefore, in this work we proved the feasibility of using classical atomic simulations, namely molecular dynamics and molecular statics, to study the piezoelectric properties of bulk and nanobelts ZnS structures, by utilizing the core-shell atomic potential model. After conducting MD simulations of bulk and nanobelts ZnO piezoelectric constants, utilizing reliable ZnO core-shell potentials, we report the bulk ZnS piezoelectric constants calculated using three different classical interatomic core-shell ZnS potentials; the Wright and Jackson (1995) potential, the Wright and Gale (2004) potential, and the Namsani et al. (2015) potential. The simulation results showed that the Wright and Gale (2004) ZnS potential, which includes a four-body bonded term, is the most reliable potential to be used for large-scale atomic simulation of piezoelectric response of the bulk ZnS structures. Utilizing the Wright and Gale (2004) potential, we further studied the effect of size scale effect on the piezoelectric response of ZnS nanobelts by conduction molecular dynamics simulations for six ZnS nanobelts with length of 91.75 A and transverse size of 22.94 - 42.06 angstrom. The results showed that, as with the ZnO nanobelts, the change of piezoelectric constant decreased with the increase of the size of the ZnS nanobelts structures.