Anisotropic microwave conductivity of cuprate superconductors in the presence of CuO chain-induced impurities

Abstract

The anisotropy in the microwave conductivity of the ortho-II ${\text{YBa}}_{2}{\text{Cu}}_{3}{\text{O}}_{6.50}$ is studied within the kinetic-energy driven superconducting mechanism. The ortho-II ${\text{YBa}}_{2}{\text{Cu}}_{3}{\text{O}}_{6.50}$ is characterized by a periodic alternative of filled and empty $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{b}$-axis CuO chains. By considering the CuO chain-induced extended anisotropy impurity scattering, the main features of the anisotropy in the microwave conductivity of the ortho-II ${\text{YBa}}_{2}{\text{Cu}}_{3}{\text{O}}_{6.50}$ are reproduced based on the nodal approximation of the quasiparticle excitations and scattering processes, including the intensity and line shape of the energy and temperature dependences of the $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{a}$-axis and $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{b}$-axis microwave conductivities. Our results also confirm that the $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{b}$-axis CuO chain-induced impurity is the main source of the anisotropy.