Excitation of Soliton-Type Waves in Crystals of the A3B Stoichiometry

Resumo

Using the method of molecular dynamics and taking Ni₃Al and Pt₃Al as examples, crystals of the A₃B composition are considered for the possibility of excitation of soliton-type waves in them. The potentials obtained by the embedded-atom method were used to describe interatomic interactions. It is shown that the harmonic external stimulus can excite waves of the soliton type in a Pt₃Al crystal, but not in Ni₃Al. Such compression–expansion waves are generated because of excitation of discrete breathers with soft nonlinearity that cannot exist in a Ni₃Al crystal near the affected region. The detected waves are capable of propagating to thousands of nanometers along the Pt₃Al crystal without losses of integrity and speed. The shape of the obtained wave corresponds to the kink solution of the sine-Gordon equation. The aggregate amount of energy transferred by a wave is determined by the number of rows of atoms involved in fluctuations; this may involve dozens and hundreds of electron volts.