Kink in dual dilaton-axion theories with potential

The representation in terms of Ernst's complex potential is used to describe and analyze dilaton-axion theories with potential. The set of such systems is divided into pairs of dual systems with respect to the inversion of the Ernst potential. Using duality, a theory is constructed that is invariant with respect to the nonlinear Ehlers transformation. For this theory, a soliton solution is obtained that is dual to a dilaton kink in a system that is invariant with respect to the axion shift transformation.