W(111) surface: an experimental and theoretical photoemission study

A detailed analysis of W(111) surface has been carried out by means of photoemission spectroscopy, together with a theoretical study of the electronic structure of the surface based on a tight binding Hamiltonian. During such a study the results from angular integrated and angular resolved ultraviolet photoemission spectroscopy have been compared with the computed surface density of states. This allowed the unique assignement of the surface sensitive features to surface states and resonances; the use of the polarized continuum of Synchrotron Radiation excitation source made possible to extend such an analysis to the determination of the state symmetries. The picture which emerges for the W(111) surface shows a remarkable feature: the surface states and resonances bands have a very small dispersion in the 2D BZ, due to the large surface atoms separation. The effect is so large that the K parallel integrated surface DOS is interpretable in terms of single d-orbital derived peaks.