Angle-resolved photoemission study of Fe on a vicinal Au (7 8 8) surface

Abstract

The electronic and magnetic nature of Fe monatomic chains and two-dimensional (2D) adlayers grown by step decoration of a vicinal Au (7 8 8) surface has been investigated by angle-resolved photoemission spectroscopy (ARPES). By comparing the coverage dependence of ARPES spectra with bulk photoemission data and band structure calculations, we found that the Fe chains have a low ferromagnetic spin state or a nonmagnetic state, and that the 2D Fe adlayers have a high ferromagnetic spin state similar to the bulk Fe. We have succeeded in mapping out the band dispersion of the Fe chains and the 2D adlayers. The band dispersion of the monatomic chains derived from the ARPES measurement show a strong anisotropic feature reflecting a one-dimensional (1D) character. On the other hand, the ARPES spectra of the 2D adlayers show a finite energy dispersion even in the direction perpendicular to the steps, implying the break down of the 1D character. These results suggest that the electronic structures and the magnetism strongly depend on the dimensionality of the Fe adatom structures.