Self-averaging of random and thermally disordered diluted Ising systems

Self-averaging of Singular thermodynamic quantities at criticality for rand omly and thermally diluted three-dimensional Ising systems has been studied by the Monte Carlo approach. Substantially improved self-averaging is obta ined for critically clustered (critically thermally diluted) vacancy distri butions in comparison with the observed self-averaging for purely random di luted distributions. Critically thermal dilution, leading to maximum relati ve self-averaging, corresponds to the case when the characteristic vacancy ordering temperature (theta) is made equal to the magnetic critical tempera ture for the pure three-dimensional (3D) Ising systems (T-c(3D)). For the c ase of a high ordering temperature (theta much greater than T-c(3D)), the s elf-averaging obtained is comparable to that in a randomly diluted system. [S1063-651X(99)11008-0].