Fundamental solitons in parity-time symmetric lattice with a vacancy defect

We put forward a mechanism for delaying the collapse of the fundamental solitons in nonlinear media whose dynamics is governed by two-dimensional nonlinear Schrödinger (NLS) equation with parity-time symmetric (PT-symmetric) periodic potentials with/without a vacancy defect. We observed that strengthened gain-loss component (imaginary part of the potential) in the periodic lattice impoverish the stability properties of the solitons, on the other hand adding a vacancy defect to the periodic PT-symmetric lattice acts as a delaying mechanism for collapsing solitons.