New attractive-force concept for Cooper pairs and theoretical evaluation of critical temperature and critical-current density in high-temperature superconductors

Abstract

We propose a new attractive interaction between pairs of holes that results in Cooper pairs and a linear temperature dependence of the spin-energy gap derived from Fermi statistics. This interaction is a Lorentz force between two moving holes with equal velocity. This force is analogous to the attractive electromagnetic force between parallel current-carrying leads; local currents exist at a CuO2 surface. Combining the spin-energy gap and the proposed attractive force, we derive a critical temperature equation that gives the dependence of critical temperature on doping. This equation contains electric charge, coherence, Debye temperature, hole concentration, and forbidden band gap. It does not contain numerical or fitting parameters. By comparing the values obtained by this equation with experimental results, we find that the proposed theory agrees with the results for doping dependence. Furthermore, we use the spin-energy gap to obtain results for the temperature dependence of critical current density.