Discrete breathers in biatomic crystals of AB and A3B composition
The conditions for the existence of discrete breathers (DBs) in biatomic crystals of AB and A3B composition are established, and their properties are studied by means of molecular mechanics using the examples of CuAu and Pt3Al, respectively. The phonon spectra of the crystals are analyzed, and a gap in the phonon spectrum of CuAu is obtained via considerable homogeneous elastic strain. There is a gap in the phonon spectrum of the Pt3Al crystal at zero strain, due to the considerable difference between the atomic weights of its components. The frequencies at which discrete breathers can exist in the considered crystals are determined. The energy localized on different types of DBs is estimated. The propagation of a current pulse through Pt3Al resulting in the excitation of DBs with mild nonlinearity is simulated.