Molecular dynamics simulations of single-layer molybdenum disulphide (MoS_2): Stillinger-Weber parametrization, mechanical properties, and thermal conductivity

摘要

We present a parameterization of the Stillinger-Weber potential to describe the interatomic interactions within single-layer MoS_2 (SLMoS_2). The potential parameters are fitted to an experimentally obtained phonon spectrum, and the resulting empirical potential provides a good description for the energy gap and the crossover in the phonon spectrum. Using this potential, we perform classical molecular dynamics simulations to study chirality, size, and strain effects on the Young's modulus and the thermal conductivity of SLMoS_2. We demonstrate the importance of the free edges on the mechanical and thermal properties of SLMoS_2 nanoribbons. Specifically, while edge effects are found to reduce the Young's modulus of SLMoS_2 nanoribbons, the free edges also reduce the thermal stability of SLMoS_2 nanoribbons, which may induce melting well below the bulk melt temperature. Finally, uniaxial strain is found to efficiently manipulate the thermal conductivity of infinite, periodic SLMoS_2.