Screening Effect in Quark-Hadron Mixed Phase

Possibility of the structured mixed phases at first order phase transitions in neutron stars is reexamined by taking into account the charge screening effect. The Maxwell construction is shown to be not conflicted with the Gibbs conditions once the Coulomb potential is properly taken into account. Taking the hadron-quark deconfinement transition as an example, we explicitly demonstrate a mechanical instability of the geometrical structure of the structured mixed phase by the charge screening effect. In this case we have effectively the picture given by the Maxwell construction.