Discrete breathers in metals and ordered alloys

Abstract

It has been rigorously proved that nonlinear lattices can support spatially localized and periodic in time vibrational modes called either discrete breathers (DBs) or intrinsic localized modes (ILMs). DB does not radiate its energy because its frequency does not belong to the spectrum of small-amplitude running waves. Discreteness and nonlinearity are often said to be the two major necessary conditions for the existence of DBs. Interatomic interactions are nonlinear and the discovery of DBs in crystals, which are nonlinear lattices at the atomic scale, was just a question of time. The first successful attempt to excite DB in alkali-halide NaI crystal in molecular dynamics simulations dates back to 1997. However, the first report on DBs in pure metals was delayed till 2011. In this review we discuss the reason of this delay, describe the latest results on DBs in pure metals and ordered alloys, and outline the open problems in this area.

Plane and plane-radial discrete breathers in fcc metals

“…Zero-dimensional DBs in N-dimensional crystal is spatially localized in N directions. Such DBs were intensively studied in the last decade [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. One-dimensional DBs, when oscillations are localized in one spatial directions and delocalized in the second one, were successfully excited in a two-dimensional graphene [19].…”