Molecular dynamic analysis of energy transport in a Pt3Al crystal under the impact in the spectrum gap frequency

Abstract

Сonstant search for new mechanisms of energy transport associated with a decrease in losses results in the active investigation of the possibilities of generating mobile excitations at frequencies outside the phonon spectrum. The effect of energy transfer at frequencies outside the band, possible in case if the excitation amplitude exceeds the critical value, was previously actively studied in reduced dimension systems. In this work, for the first time, the possibility and features of energy transfer at frequencies outside the phonon spectrum of a crystal are studied on the Pt 3 Al biatomic lattice, the corresponding excitations in which are created through the implementation of harmonic vibrations at frequencies lying in the phonon spectrum gap. It was found that as a result of the initial impact, the parameters of which lie in the band gap, at the first stage, discrete breathers are formed on aluminum atoms lying in the immediate vicinity of the impact zone. The threshold value of the energy required to excite breathers, determined by the amplitude and frequency of exposure, decreases as the frequency approaches the boundary of the slit in the spectrum. At the second stage, after the end of the harmonic action, a soliton-like wave is formed, moving along the crystal with an average speed of 4.5 km / s. The wave velocity is practically independent of the initial disturbance amplitude. The shape and amplitude of the moving wave are weakly dependent on the initial frequency. Significant differences in the profile and a tendency to bimodality were revealed only when exposed to frequencies close to the lower limit of the spectrum. The results obtained contribute to a fundamental understanding of the features of the propagation of elastic disturbances in nonlinear media in case of forbidden zones region impacts.

The Influence of Crystal Anisotropy on the Characteristics of Solitary Waves in the Nonlinear Supratransmission Effect: Molecular Dynamic Modeling

“…The experimental setup was similar to the one described in [44,55]. Here, we will discuss the details the experimental procedure for investigating the effect of nonlinear supertransmission as a function of crystal lattice orientation.…”

“…Discrete structures are extremely extensive, with crystalline materials, particularly metals and alloys, being one of the broadest classes. This study focuses on a crystal of stoichiometry A 3 B, supporting discrete breathers and the effect of nonlinear supratransmission [43][44][45][46][47]. The manifestation of this effect has been examined in our previous works [44][45][46].…”

“…This study focuses on a crystal of stoichiometry A 3 B, supporting discrete breathers and the effect of nonlinear supratransmission [43][44][45][46][47]. The manifestation of this effect has been examined in our previous works [44][45][46]. Here, a more detailed analysis of the role of crystal anisotropy on the characteristics of solitary waves excited as a result of the NST effect will be conducted.…”