Two-component localized vibrational modes in fcc metals

OV Bachurina and AA Kudreyko, EUROPEAN PHYSICAL JOURNAL B, 94, 218 (2021).

DOI: 10.1140/epjb/s10051-021-00227-3

Discrete breathers (DB) are spatially localized vibrational modes of large amplitude in a defect-free crystal lattice. In this work, for the first time, two-dimensional DBs based on a two-component delocalized nonlinear vibrational mode (DNVM) are excited in a single (111) close- packed atomic plane in fcc metals (Al, Cu, and Ni). DNVM provides a pattern according to which the initial displacements of atoms from their equilibrium lattice positions are set. Classical molecular dynamics simulations have demonstrated the possibility to excite a long-lived two-dimensional DB with the energy of the order of 0.5-1.0 eV per oscillating atom. The two-dimensional DBs have a hard-type of nonlinearity and a lifetime of 12-24 ps, after which they decay into one-dimensional DBs, which, in turn, decay into zero-dimensional DBs, which also have a sufficiently long lifetime. A new class of two- dimensional DBs expands our understanding of the variety of spatially localized vibrational modes in nonlinear fcc lattices.

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