MONTE-CARLO RENORMALIZATION-GROUP STUDY OF THE SITE-DILUTED SIMPLE CUBIC ISING-MODEL

The Monte Carlo renormalization group approach is discussed with special emphasis on the accurate determination of the critical temperature for diluted systems, and it is applied to study the critical behaviour of site-diluted simple cubic Ising models. The method combines the merits of the Monte Carlo simulations and the real-space renormalization calculations while simultaneously avoiding their respective disadvantages, and it therefore can yield additional information commonly not available by the individual methods, especially concerning the width of the asymptotic critical regime. The results for impurity concentrations 0 less-than-or-equal-to x less-than-or-equal-to 0.2 are compared with those of conventional Monte Carlo simulations and k-space renormalization calculations.