Potassium adsorption and an unoccupied surface state on Fe(001)

Spin-polarized photoemission studies of potassium adsorption on an Fe(001) surface provide evidence of a minority-spin surface state sitting immediately above the Fermi level on the clean surface. This state of symmetry is associated with the surface state predicted in first-principles calculations and the state utilized in chemically selective scanning tunnelling microscopy studies of the Fe(001) surface.