The influence of correlated hopping on the ground-state properties of the two-dimensional Falicov-Kimball model

The extrapolation of finite cluster calculations is used to study effects of correlated hopping on the ground-state properties of the two-dimensional Falicov-Kimball model (FKM). It is shown that the ground-state phase diagram as well as the picture of valence transitions found for the conventional FKM (without correlated hopping) are strongly changed when the correlated hopping term is added. In particular, it is found that non-zero values of correlated hopping stabilize a new type of spatial charge ordering, the axial stripes, for a wide range of model parameters. This result indicates that the competition between the kinetic energy, the on-site Coulomb energy and the correlated hopping term can be an alternative mechanism leading to stripe formation in the strongly correlated electron systems.