Thermal conductivity of ferroelectrics with hydrogen bonds

In Kobayashi's model of ferroelectrics with piezoeffect in paraphase the operators of heat currents are derived. Then the retarded Green functions of pseudospins and phonons are found and the heat conductivity is calculated in the Kubo formalism near the Curie point. When comparing the theory with the experiment it turns out that the theory gives the correct critical singularities of the heat conductivity of Rochelle salt whereas for KDP-like ferroelectrics the Kobayashi model appears to be inadequate.