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

The anisotropy in the microwave conductivity of the ortho-II YBa${}_2$Cu${}_3$O${}_{6.50}$ is studied within the kinetic energy driven superconducting mechanism. The ortho-II YBa${}_2$Cu${}_3$O${}_{6.50}$ is characterized by a periodic alternative of filled and empty $\widehat{b}$-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 YBa${}_2$Cu${}_3$O${}_{6.50}$ are reproduced based on the nodal approximation of the quasiparticle excitations and scattering processes, including the intensity and lineshape of the energy and temperature dependence of the $\widehat{a}$-axis and $\widehat{b}$-axis microwave conductivities. Our results also confirm that the $\widehat{b}$-axis CuO chain induced impurity is the main source of the anisotropy.