Phase transitions induced by a defect in a growing interface model

The effect of a localized defect on the profile of a one-dimensional growing interface is considered. The ( q, q ′) phase diagram of a restricted solid-on-solid growth model is studied within the mean field approximation, where q ′ and q are the intrinsic growth rates of the defect site and of all other sites, respectively. It is found that the model exhibits two types of phase transitions: One separating vanishing slope and non-vanishing slope interfaces, and the other separating interfaces whose slope varies continuously with the defect parameter q ′ from those whose slope is independent of q ′.