Pairing mechanism for electron-doped cuprates in a layered two-dimensional electron gas model Original Research Article

An effective two-dimensional (2D) interaction potential for super-lattice of electron-doped cuprates (Nd2−xCexCuO4) treated as a layered electron gas is developed which incorporates screening of electrons as carriers by phonons and by plasmons. The layer stacking sequence is modelled with single superconducting CuO2 layer, which is an isolated free electron layer well, separated by the charge reservoir layers. A model dielectric function in the random phase approximation is set up for two oscillators fulfilling the appropriate sum rules on polarisabilities. Attention is focussed on the description of the inter-layer electron pairing and superconducting transition temperature, Tc. Deduced values of the Coulomb repulsive parameter and of the electron–phonon coupling strength from the 2D effective interaction potential indicate that the Nd-doped cuprate superconductor is in the strong coupling regime with effective screening of the electrons. The superconducting transition temperature of Nd1.85Ce0.15CuO4 is estimated as 28 K, which is consistent with the reported data. The implications of the proposed approach and its analysis are discussed.