Electronic properties and magnetism in high-T_{c} superconductors

The first self-consistent spin-polarized band-structure calculations have been performed for ${\mathrm{CuO}}_2$ planes in the high-$T_c$ superconductors. It has been demonstrated that due to different doping a magnetic transition occurs. The calculated magnetic moment for the (${\mathrm{CuO}}_2$ ${)}^{\mathrm{-}\mathrm{-}}$ unit plane is equal to 1.0${\mu }_B$ while the (${\mathrm{CuO}}_2$ ${)}^{\mathrm{-}}$ plane is nonmagnetic. These charge- and spin-density fluctuations, strongly related, are probably responsible for the observed high transition temperature in these new superconductors. In agreement with experiment the density of states at the Fermi energy is very low.