Dependence of the superconducting critical temperature on the number of layers in a homologous series of high-Tc cuprates

Abstract

We study a model of n-layer high-temperature cuprates of homologous series like HgBa2Can−1CunO2+2n+δ to explain the dependence of the critical temperature Tc(n) on the number n of Cu−O planes in the elementary cell. Focusing on the description of the high-temperature superconducting system in terms of the collective phase variables, we have considered a semimicroscopic anisotropic three-dimensional vector XY model of stacked copper-oxide layers with adjustable parameters representing microscopic in-plane and out-of-plane phase stiffnesses. The model captures the layered composition and block structure along the c axis of homologous series. Implementing the spherical closure relation for vector variables we have approximately solved the phase XY model with the help of the transfer matrix method and calculated Tc(n) for arbitrary block size n, elucidating the role of the c-axis anisotropy and its influence on the critical temperature. Furthermore, we accommodate inhomogeneous charge distribution among planes characterized by the charge imbalance coefficient R being the function of number of layers n. By making a physically justified assumption regarding the doping dependence of the microscopic phase stiffnesses, we have calculated the values of the parameter R as a function of block size n in reasonable agreement with the nuclear magnetic resonance data of the carrier distribution in multilayered high-Tc cuprates.

Source-reported materials — not catalogue approval

Similar papers