Solitons in superlattices

Negative differential conductivity in superlattices leads to the growth of inevitable spatial fluctuations. The spatially homogeneous electron distribution then becomes unstable, and a propagating electron accumulation-layer domain is formed. It is shown that envelopes of the wave functions are governed by the nonlinear Schrödinger equation which has soliton solutions, the result of which suggests soliton formations and propagations in superlattices.