Surface phase diagrams of a random transverse Ising model

The effect of surface on the critical behaviour of a ferromagnetic Ising sp in model in a random transverse surface and bulk fields is studied by the u se of an effective field method within the framework of a single-site clust er theory. The state equations are derived using a probability distribution method based on the use of Van der Waerden identities. The complete phase diagrams are investigated when the transverse fields are bimodally and trim odally distributed. In particular, the influence of the transverse fields, exchange interaction strength ratio and the distribution parameter on the p hase diagrams behaviour is examined in detail.