Friedel-type oscillations in one-dimensional antiferromagnetic insulators

An impurity spin in one-dimensional spin- ½ X-Y and antiferromagnetic Heisenberg models is shown to induce decaying spatial oscillations of magnetization for finite magnetic field. The wavelength of oscillation changes with magnetic field. Since these systems can be described mathematically in terms of a degenerate gas of pseudofermions, their response to impurity perturbation is similar to the response of an electron gas to a localized static charge