Superfluid Response In Electron Doped High-Temperature Superconductors

High temperature superconducting electrical has been a hot issue in study of condensed matter physics, electronic pairing symmetry is one of this core issues. For hole-doped cuprate superconductors, it is commonly accepted that the pairing order parameter has d_x²-y²-wave symmetry. However, for electron-doped cuprate superconductors, the pairing order parameter has d_x²-y²-wave symmetry or s-wave symmetry, it is a big dispute.Superconducting superfluid density is an important parameter connected with the microscopic mechanism of superconductivity and macroscopic electromagnetic, in the linear approximation. d_x²-y²-wave superconductors superfluid density is temperature of linear functions at low temperature, s-wave superconductors superfluid density is an exponential function of temperature. It was found that, electron-doped superconductors superfluid density with temperature is more complex, in the underdoped regime superfluid density varies quadratically with temperature, in agreement with the theoretical prediction for a d_x²-y²-wave superconductor with impurity scattering; in the overdoped regime the superfluid density exhibits an exponential temperature dependence like s-wave superconductors. These results indicate that from the underdoped to the overdoped there is a d_x²-y²- wave to anisotropic s-wave transition. Understand the superfluid response experimental data, from the symmetry of superconducting pairing information is the core content of this paper.This paper first from the micro t-t′-t″-J model, by slave-boson mean-field approximation, contains the antiferromagnetic correlation order and superconducting pairing items arriving at the two-band superconducting Hamilton thus deduce two superfluid density. Through the superfluid with different doping levels and response to the comparison of experimental data, found that using two different ranges with d_x²-y²-wave, theories and experiments in accordance with good. Therefore, the electron-doped superconducting pairing symmetry is same as the hole-doped superconducting, as a d_x²-y²-wave, symmetry, consistent with the earlier two band models by phenomenological. The superfluid density changes with doping, is because of quasi-particles in two band accompany with interaction with the doping.