Supersonic crowdion clusters in 2D Morse lattice

Publication date: Available online 3 October 2019Source: Physics Letters AAuthor(s): I.A. Shepelev, E.A. Korznikova, D.V. Bachurin, A.S. Semenov, A.P. Chetverikov, S.V. DmitrievAbstractFor the first time, the class of simple N-crowdions is expanded to M×N-crowdions, dynamics of which is investigated in two-dimensional triangular Morse lattice by means of molecular dynamics simulations. The M×N-crowdions are excited by giving initial velocity V0 to the chosen M×N block of atoms along a close-packed direction. In the notations here N is the number of neighboring atoms in one close-packed row and M is the number of neighboring rows. The 2×1, 2×2 and 2×4-crowdions are chosen for consideration. It is found that the 2×1 and 2×2-crowdions demonstrate stable dynamics, while the 2×2-crowdions propagate longer distances and need less energy for their excitation in comparison with the 2×1 and classical 1×1-crowdions. Unlike the first two, the 2×4-crowdions are unstable and transform very quickly into the 2×2-crowdions by losing interstitials, which are quasi-immobile and inclined by 60° with respect to the direction of the initial velocity vector. Maximal distances travelled by the crowdions as functions of initial velocity are calculated. The 2×2 and 2×4-crowdions are found to be the most effective in mass transfer. The defect structure arising in the crystal as a result of initiation of M×N-crowdions and its dependence on the initial velocity is discussed.

Source: Physics Letters A - October 4, 2019 Category: Physics Source Type: research