The connection of the charge density waves and superconducting state in the two-fluid model of superconductivity in HTSC
The physical properties of different types of HTSC are analyzed in the two-fluid model of superconducting (SC) state formation depending on the different location of SC slots D и Δ<sub>1</sub> in the energy spectra. In this model, when doping with oxygen in CuO<sub>2</sub> planes the charge density waves (CDW) formed in the oxygen anion system are transformed into local electron pairs (LEP) by Cu ion oscillations at T <sup>*</sup>. At T<sub>c</sub> < T <sup>*</sup> LEP create an SC state and a gap Δ<sub>1</sub>. Besides, there is a restructuring of the p and d bands. The band gap DE decreases. At D E ~ Δ<sub>1</sub> decaying LEP are transferred from the occupied States of the p band of oxygen anions to the free d subband of Cu ions because of the thermal excitation. The SC state and the d -type gap Δ in the d subband can be connected to the antiferromagnetic (AF) fluctuations. In tunnel experiments without oxygen anions and oscillating Cu ions, the LEP experience strong Coulomb repulsion of electrons. Therefore, the LEP and Δ<sub>1</sub> respectively will be strongly distorted in contrast to the slight change in the Cooper pairs of conventional superconductors in such experiments. It seems that the LEP are transitioning into another state, which can be called a state of CDW type with pseudo-gap Σ. It is also necessary to take into account minor changes in the electron pairs and the second gap Δ created by the antiferromagnetic fluctuations.