Hole-phonon coupling in high-T_c superconductors

Abstract

A new type of k space pairing interaction is proposed, which is induced by the electron(hole)-lattice coupling and which exists in crystals with elementary cells composed of several atoms as, for example in the high-T _c systems. The interaction leads to an attractive coupling between charge carriers of arbitrary k vectors. For systems characterized by quasi-two-dimensional motion of charge carriers with small Fermi wave-vectors the superconducting transition temperature T _c turns out to be proportional to the Fermi energy E _F. Experimental consequences are briefly discussed in the light of high-T _c materials.