Bond-charge repulsion and hole superconductivity

Physica C 158, 326 (1989)

It is proposed that a bond-charge repulsion term that necessarily arises in deriving a tight-biding Hamiltonian from first principles plays a fundamental role in superconductivity. This term is repulsive for bonding states and attractive for antibonding states. Together with the reduction of the local Coulomb repulsion due to atomic polarization this effect can explain the occurrence of superconductivity in solids without involving the electron-phonon interaction.