Development and Application of a ReaxFF Reactive Force Field for Ni-Doped MoS2

The properties of MoS2 can be tuned or optimizedthroughdoping. In particular, Ni doping has been shown to improve the performanceof MoS2 for various applications, including catalysis andtribology. To enable investigation of Ni-doped MoS2 withreactive molecular dynamics simulations, we developed a new ReaxFFforce field to describe this material. The force field parameterswere optimized to match a large set of density functional theory (DFT)calculations of 2H-MoS2 doped with Ni, at four differentsites (Mo-substituted, S-substituted, octahedral intercalation, andtetrahedral intercalation), under uniaxial, biaxial, triaxial, andshear strain. The force field was evaluated by comparing ReaxFF- andDFT-relaxed structural parameters, the tetrahedral/octahedral energydifference in doped 2H, energies of doped 1H and 1T monolayers, anddoped 2H structures with vacancies. We demonstrated the applicationof the force field with reactive simulations of sputtering depositionand annealing of Ni-doped MoS2 films. Results show thatthe developed force field can successfully model the phase transitionof Ni-doped MoS2 from amorphous to crystalline. The newlydeveloped force field can be used in subsequent investigations tostudy the properties and behavior of Ni-doped MoS2 usingreactive molecular dynamics simulations.

Automated summary

The properties of MoS2 can be improved through Ni doping, and a new force field called ReaxFF is developed to describe this material. The force field parameters are optimized to match the DFT calculations of Ni-doped MoS2 at different doping sites and under different strains. The force field can successfully model the phase transition of Ni-doped MoS2 from amorphous to crystalline, and it can be used for further investigations of Ni-doped MoS2 using reactive molecular dynamics simulations.