Spin susceptibility of cuprates in the model of a 2D frustrated antiferromagnet: Role of renormalization of spin fluctuations in describing neutron experiments

Experimental data on the spin susceptibility of HTSC cuprates are reproduced on the basis of a spherically symmetric approach in the frustrated Heisenberg model. The inclusion of real and imaginary renormalizations in spin Green's functions makes it possible to explain the evolution of spin excitation spectrum omega(q) and susceptibility spectrum chi(q, omega) in the range from insulator to optimal doping. In the low-frustration limit corresponding to the weakly doped mode, the saddle singularity of omega(q) and scaling of chi(2D)(omega) = integral dq Im chi(q, omega) are reproduced and an analytic expression is derived for the scaling function. In the strong frustration (optimal doping) mode, the stripe scenario is demonstrated; this leads to a peak of chi(2D) (omega) in the region of omega similar to 60 meV.