Spin and superconducting fluctuations in copper-oxygen planes of quasi-two-dimensional HTSC

The 2D XY Berezinskii-Kosterlitz-Thouless model for quasi-two-dimensional HTSC is used to study the peculiarities of two dimensional superconducting and spin fluctuations in the CuO2 planes at T < T*, where T* is the charge ordering temperature. It is shown that the semiconducting character of charge transfer along the c-axis is strengthened by the coexisting metallic, dielectric, and superconducting phases which are independently distributed in each of the CuO2 planes. This leads to two channels of charge tunneling with different temperature dependences of probability tc(T). Temperature dependence of out-of-plane resistivity were derived, which made it possible to determine the temperature of 2D XY ordering of copper spins in dielectric stripes and dimensionality of the superconducting transition. (Author)