M. Potthoff et W. Nolting, SURFACE MAGNETISM IN THE STRONGLY CORRELATED HUBBARD-MODEL, Physical review. B, Condensed matter, 55(5), 1997, pp. 2741-2744
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.