  While classical theory of phase transitions deals with systems where shape
variation is energetically neutral, the account of rigidity can lead to the
emergence of new thermodynamic features. One of them is a special type of
critical points that are characteristic of phase transitions specifically in
solids. We develop a general theory of such rigidity-induced critical points
and illustrate the results by analyzing in detail the case of an isotropic,
geometrically nonlinear solid undergoing a volumetric phase transition at zero
temperature.
