Staggered magnetic susceptibility in high-Tc systems: A scaling approach.

A scaling theory is applied in order to calculate the temperature dependence of the staggered magnetic susceptibility associated with the anti-ferromagnetism observed in high-temperature superconductors. In a logarithmic approximation, only a summation of the leading square logarithmic terms are taken into account, assuming the parquet approximation. We show that scaling theory can be applied to the square logarithmic two-dimensional problem. The scaling method is an improvement compared to the alternative random-phase approximation method. Our scaling result explains the temperature and doping dependence of the nuclear-spin-lattice relaxation time observed in high-Tc systems to satisfaction. However, the results of this paper indicate that the logarithmic parquet approximation may not be sufficient to calculate quantitatively the magnetic susceptibility. Ways to improve the theory are discussed.