Excitation of Breather (Bion) in Superlattice

Abstract

Soliton breather excitation in superlattices been studied in this paper. It is observed that under certain conditions, the vector potential equation for the electromagnetic wave propagating through the superlattice assumes the sine-Gordon(sG) equation, the solution of which does not give only a soliton but also a soliton breather. The binding energy of the breather is calculated to be Eb = 16γ(1 - sin ν), γ = (1 - (u2/ν20)-1/2 where u is the velocity of the breather and ν0 is the velocity of the electromagnetic wave in the absence of electrons. As can be seen, when ν → (π/ 2) the binding energy tends to zero, hence, the breather disintegrates into a soliton and an antisoliton. It was further observed that the binding energy decreases with an increase in Δ (the half miniband width), for a given value of d (SL period). Similarly it also decreases with increasing d for a given value of Δ. Comparing the breather's rest energy Eb to that of the soliton Es we find Eb = 2Es sin ν. We noted that the breather's rest energy is less than that required to excite a soliton.