Electron band structure of a rare-earth metal: Tb(0001)

The electron band structure of Tb metal has been determined at room temperature by means of angle-resolved photoemission experiments on Tb(0001). For the first time in any rare-earth metal, the full dispersed 6s-5d3z2-1-type 1 band has been experimentally mapped along the A line. The two critical points of the 1 band have been determined at 1+=-6.9 eV and 4-=-3.6 eV. Dispersion and width of the initial 1 band are in good agreement with relativistic linear muffin-tin orbitals calculations, but the absolute energy position deviates by -1.5 eV from theory. [1+(calc)=-5.3 eV and 4-(calc)=-2.3 eV.] The initial 1 band lies well below the Fermi level, also in agreement with theory, and the experimental value of the 4f binding energy is about -2.6 eV.