An intralayer pairing mechanism for the coexistence of charge- and spin-density waves induced superconductivity in LaSrCuO

Abstract

Starting from an effective two-dimensional dynamic interaction that includes screening of holes as carriers by charge density fluctuations and by optical phonons, we investigate the nature of a d-wave pairing mechanism leading to superconductivity in layered La-based cuprates. We consider the La–Sr–CuO system as an ionic solid containing layers of holes as carriers with a single CuO2 layer in a unit cell, where the localized spins form an antiferromagnetic (AF) order. The electron–phonon interaction matrix element in the case of an ordinary unit cell without the local AF order yields s-wave superconductivity. While for the unit cell with AF order, the wave-vector dependence of the intralayer effective interaction potential shows the sign reversal to create d-wave pairing due to localized antiferromagnetic spin order for the screened phonons. Following the strong coupling theory, the superconducting transition temperature, the isotope exponent, coherence length and magnetic penetration depth are also estimated. The implications of the intralayer pairing model and its analysis are discussed.