Spin-phonon-electron correlations in high-temperature superconductors

Spin excitation (spin fluctuation) spectra in the superconducting phases of hightemperature $La_{2-x}Sr_xCuO_4$ - and $YBa_2Cu_3O_{7-y}$-type superconductors are considered, as well as tl1eir influence 011 tl1e therшodynamic characteristics of these compounds, primarily on tl1eir low-temperature heat capacity, which is shown to have а power dependeпce on temperature. In the region of values of the $k\simeq k_F$ (Тikp is the Fermi momentum) wave vector, the spectra of coupled spinphonoп vibratioпs responsiЫe for the appearance of coupled electron pairs in the superconducting state are analyzed. It is shown that the critical temperature $Т_с$ of high-temperature superconductors, determined Ьу the. spin-phonon coupling parameter $\tilde{\zeta}$, is limited for tl1e compounds studied, which motivates а more detailed coпsideration of spin-electron correlations in high-temperature superconductors.