Static and dynamic structure factors in three-dimensional randomly diluted Ising models

Abstract

We consider the three-dimensional randomly diluted Ising model and study the critical behavior of the static and dynamic spin-spin correlation functions (static and dynamic structure factors) at the paramagnetic-ferromagnetic transition in the high-temperature phase. We consider a purely relaxational dynamics without conservation laws, the so-called model A. We present Monte Carlo simulations and perturbative field-theoretical calculations. While the critical behavior of the static structure factor is quite similar to that occurring in pure Ising systems, the dynamic structure factor shows a substantially different critical behavior. In particular, the dynamic correlation function shows a large-time decay rate which is momentum independent. This effect is not related to the presence of the Griffiths tail, which is expected to be irrelevant in the critical limit, but rather to the breaking of translational invariance, which occurs for any sample and which, at the critical point, is not recovered even after the disorder average.

43 pages

References in corpus (5)

• Rare region effects at classical, quantum, and non-equilibrium phase transitions
• The critical exponents of the superfluid transition in He4
• Critical behavior of Griffiths ferromagnets
• Magnetic-glassy multicritical behavior of the three-dimensional +- J Ising model
• Relaxational dynamics in 3D randomly diluted Ising models