  Using a 2D model of capacitively coupled Josephson junction arrays (created
by a network of twin boundary dislocations with strain fields acting as an
insulating barrier between hole-rich domains in underdoped crystals), we study
the influence of chemical pressure on nonlinear thermal conductivity (NLTC) of
an intrinsically granular superconductor. Quite a substantial enhancement of
NLTC is predicted when intrinsic chemoelectric field closely matches the
externally produced thermoelectric field. The estimates of the model parameters
suggest a realistic possibility to experimentally monitor this effect in
non-stoichiometric superconductors.
