Effect of charge ordering on superconductivity in high-temperature superconductors

It is shown that charge ordering in layered crystalline metals causes an increase in the normal state energy of the conducting layers. If this increase in the energy exceeds the difference between the superconducting state energy and the normal state energy of the metal, then the superconducting transition occurs. A relation between the charge gap in the superconducting phase and the bandgap width in the undoped insulating phase of high-temperature superconductors is obtained.