The non-linear spectrum of a two-dimensional electron gas (2-DEG) formed at
the interface of a heterostructure is investigated. This spectrum is found
to contain a new type of localized excitation exhibiting soliton behavior.
A matrix formulation of the model equations permits the extraction of the
equation of evolution in space for these excitations. Results are presented
for the boundary value problem excited by temporal Gaussian pulses. (C) 19
99 Published by Elsevier Science B.V.