Computer Experiments on Soliton Production for Realizing Laboratory Experiments

Molecular dynamics computer experiments have been carried out for two-dimensional hexagonal mass-spring model crystals. Anharmonic forces up to the third order were taken into account, and central forces were considered between the nearest neighbor atoms. Input pulse displacements were given to atoms on the crystal surface, and induced displacements and velocities of all atoms in the crystal were computed. Solitons were produced as the atomic excitation, and the propagation velocity and the strength of solitons were enumerated. The dependences of these two quantities on the pulse application direction and on two parameters, the magnitudes of the input pulse and the higher order force constant, were investigated. Two crystallographic directions were taken for the input pulse direction, and values of the two parameters were widely varied. On the basis of the results of the simulation, a possible laboratory experiment of soliton production was considered.