Effect of elastic deformation on phonon spectrum and characteristics of gap discrete breathers in crystal with NaCl-type structure

The influence of elastic deformation on the phonon spectrum and properties of the gap discrete breathers (DBs) in a crystal with the NaCl type structure and significantly different masses of anions and cations has been studied using the molecular dynamics method. Two modes of the crystal deformation were considered, including the (i) hydrostatic tension and compression and (ii) pure shear. It is established that the phonon densities of states are significantly changed in both cases, while the gap DB frequencies depend on the hydrostatic tension and compression and are almost independent of the pure shear.