Cooper-like Pairing and Energy Gap Induced by Ion Electronic Polarizability

Abstract

We explore the possibility that the ionic electron polarizabilities of the oxygen ions in the cuprates and the bismutates and the polarizabilities of As and Se ions in the iron pnictides contribute to charge carrier pairing leading to high Tc superconductivity. Using the fact that the ionic polarization response to a change in the electric field is practically instantaneous we find, that the inter carrier electrostatic potential is attractive in a limited distance range. This potential is used to calculate quantum mechanically the cooper-like pairing energy and wavefunction and the gap energy showing they are consistent with pairing and gap energies of high Tc superconductors. Qualitative considerations suggest that this model may explain a number of important features of high Tc superconductors.

Resonant Inelastic X-ray Scattering Study of Electron-Exciton Coupling in High-Tc Cuprates

“…When interacting holes form Cooper-pairs, the resulting change of their effective mass may stabilize the superconducting state [8]. On a microscopic scale a pairing-induced modification of the bare density response function [9], magnon mediated-interactions [10,11], plasmon-mediated interactions [12], pairing mediated by the ionic electron polarizabilities [13,14], and exciton-mediated pairing [15,16] derive from the Coulomb interaction between the electrons, which does not involve lattice degrees of freedom in contrast to phonon-mediated pairing [17]. The possibility of exciton-mediated pairing has been pioneered in the context of organic materials [18], and sandwich structures [19][20][21].…”