Calculated cleavage behavior and surface states of LaOFeAs

The layered structure of the iron-based superconductors gives rise to a more or less pronounced two dimensionality of their electronic structure, most pronounced in LaOFeAs. Consequences are distinct surface states to be expected to influence any surface sensitive experimental probe. In this work a detailed density-functional analysis of the cleavage behavior and the surface electronic structure of LaOFeAs is presented. The surface states are obtained to form two-dimensional bands with their own Fermi surfaces markedly different from the bulk electronic structure.