Reexamination of the electron band structure of Tb along the ΓΔAline

The electron band structure of Tb metal has been reexamined by means of angle-resolved photoemission experiments on Tb(0001) samples free of Fe impurities in the surface region. Comparison of the present data with those collected from an Fe-contaminated sample shows that the presence of Fe in the surface region caused a shift of the top portion of the 6s-5d3z²-1-type Δ₁ band toward larger binding energies by approximately 1 eV. The energy position of the top of the Δ₁ band ( Γ₄^-) is -2.6 eV. The agreement with the result of the relativistic linear-muffin-tin-orbital calculation reported earlier (E_Γ4^-=-2.3 eV) is markedly improved.