Contribution of the surface dipole to deformation of superconductors

The interaction of the ionic lattice with the superconducting condensate is treated in terms of the electrostatic force in superconductors. It is shown that the surface dipole supplies the force responsible for the volume difference of the normal and superconducting states. Assuming this mechanism, we argue that the usual parametrization of the theory of deformable superconductors should be revisited.