Impact of the lattice period on the stability dynamics of defect solitons in periodic lattices

Abstract

The dynamics of fundamental solitons is examined for periodic and defective lattices when the lattice period is varied. The existence domain and stability intervals of solitons are determined and it is shown that the solitons can exist and stay stable for a wide range of parameters. It is observed that the domain of existence is extended by increased lattice period for the periodic lattice and the square lattice with an edge dislocation. It is also demonstrated that stability of solitons around a vacancy defect and near edge dislocation can be improved by decreased lattice period, whereas a higher lattice period supports the stability of periodic lattice solitons. Further, it is shown that there are a lower limit for the period of a square lattice and an upper limit for the period of a lattice with a vacancy defect for no collapse of the solitons in their entire existence domains. Thus modification of the lattice period provides great controllability of the soliton dynamics. It is also observed that the deeper (or strong) vacancy defect in the lattice extends the stability domain of solitons for larger lattice periods.