One-dimensional Fe surface states confined by self-assembled carbon chains at the Fe(001) surface

A c($3\sqrt{2} \times \sqrt{2}$) reconstructed structure of the Fe(001) surface with self-assembled C zigzag chains has been recently observed experimentally. Using ab initio density-functional calculations, we address the effect of the C zigzag chains on the electronic structure of this surface. We find that the formation of the C chains produces one-dimensional surface states localized along the zigzag chains. These states are spin-polarized and derive from preexisting two-dimensional Fe $d_{3z^{2}-r^{2}}$-like surface states of the clean Fe(001) surface. The simulation of the STM image allows us to assign the chain-like structure, observed in STM experiments, to the one-dimensional Fe surface states laterally confined within the C zigzag stripes.