IN-PLANE OXYGEN BREATHING AS MECHANISM OF SUPERCONDUCTIVITY IN CUPRATE HIGH TC MATERIALS

Abstract

The electron-phonon coupling constant in cuprate high temperature superconductors has been determined by acoustic method.  A direct proportional relation between the electron-phonon coupling constant in the Van Hove scenario (which is 10-100 times smaller than the conventional BCS-type) and the transition temperature is observed.  Our results show the importance of interplay between the Debye frequency and electron-phonon coupling in the two dimensional system and their variations have combined effect in governing the transition temperature.  The electron-phonon coupling constant l_vH in this scenario is in the range of 0.02 – 0.05, consistent with Cooper pair formation by in-plane oxygen breathing.