CRITICAL-BEHAVIOR AT DIRTY SURFACES .2. RG ANALYSIS OF A BULK TRICRITICAL SYSTEM WITH QUENCHED SURFACE-ENHANCEMENT DISORDER

According to the general irrelevance/relevance criteria of the Harris type dicussed in the foregoing paper, short-range correlated quenched surface-enhancement disorder is a marginal perturbation at the special (surface) transition of a 3 d bulk tricritical system. In order to determine whether the pure system critical behavior at this surface transition is stable with respect to such disorder, a detailed field-theoretic renormalization group analysis of an appropriate semi-infinite O(n) model is presented in d=3 and d=3-ε dimensions, using the replica trick. While for ε>0 a new random fixed point {Mathematical expression} as well as an (unphysical fixed point ∼e{open}1/3 is found, the pure system critical behavior in the n=1 case turns out to be stable with respect to weak enhancement disorder, both for d=3 and slightly below. © 1990 Springer-Verlag.