Nonlinear supratransmission effect in the model AB stoichiometric alloys with the B1 superstructure

This paper investigates the nonlinear supratransmission (NST) effect in model diatomic FCC alloys with a B1 superstructure. Using the molecular dynamics method in the LAMMPS software package and the Morse potential, the influence of crystal lattice anisotropy — specifically, the 100, 110, and 111 directions — on the manifestation of the NST effect is analyzed. It is established that the supratransmission of energy deep into the crystal lattice is realized through the simultaneous action of two fundamental mechanisms. The first mechanism consists of the excitation of a compression soliton wave, the energy of which is concentrated predominantly on the heavy atoms of the alloy. The second mechanism is associated with the formation and movement of hard-type discrete breathers (DBs), which localize energy on the light sublattice. Special attention is paid to the dependence of wave characteristics on the direction of propagation: the amount of energy carried by solitons consistently decreases with an increase in the atomic packing density along the selected crystallographic row. The propagation speed of the generated solitons remains unchanged when varying the parameters of the harmonic impact, being determined solely by the direction and stiffness of the interatomic bonds. For discrete breathers, two possible mobility regimes are recorded: joint movement with a soliton wave at the same speed and independent high-speed movement, which requires significant energy expenditure. Thus, it is proven that the geometry of the structure and the physical-mechanical properties of the atomic rows act as key factors determining the dynamics of nonlinear waves and the nature of energy supratransmission.