Amplitude breathers in diatomic peierls systems

Persistent non-linear oscillations-breathers-are studied in a dimerised one-dimensional electron phonon system as a function of an alternating on-site potential +or- alpha. Dimerisation is present if alpha Delta O, where 2 Delta O is the electronic gap in the ground state. The authors show the existence of breathers in the adiabatic limit by both analytic expansions and numerical dynamics. For alpha or=0.3 Delta O however, the breathers become progressively unstable towards pattern doubling. Semi-classical quantisation also shows an instability at alpha or approximately=0.75. Delta O. Electron-hole excitations form a kink-anti-kink pair for all alpha Delta O, and are accompanied by a breather when alpha or approximately=0.2 Delta O.