SURFACE MAGNETISM IN THE STRONGLY CORRELATED HUBBARD-MODEL

A generalization of a self-consistent moment method is applied to the semi-infinite Hubbard model for the (100) surface of a bcc crystal. Us ing this method, surface magnetism in the strongly correlated Hubbard model is investigated. We find the top-layer magnetization to be alway s strongly enhanced. Varying the average band occupation, a phase tran sition between ferromagnetic and antiferromagnetic order is observed w hich is confined to the very surface. Below a critical occupation, an antiferromagnetic surface can coexist with a paramagnetic bulk.