Inverse photoemission from V, Cr, Mn, Fe, and Co monolayers on Ag(100)

Well ordered 1×1 monolayers of transition metals are grown on Ag(100) at 440 K. Using inverse photoemission we obtain the position of the unoccupied 3d states versus band filling. At ${\mathit{k}}^{\mathrm{\parallel }}$=0 the minority-spin state of ${\mathrm{\Delta }}_5$ symmetry (${\mathit{d}}_{\mathit{x}\mathit{z},}$yz) is found at 2.1, 1.6, 1.4, 0.5, and 0.25 eV above the Fermi level for V, Cr, Mn, Fe, and Co monolayers. For V a majority-spin feature is observed at 0.7 eV. For the Cr monolayer we obtain a magnetic exchange splitting of 2.7 eV using previous photoemission results for the majority-spin state. This is 20 times as large as in bulk Cr, suggesting a strong enhancement of the local magnetic moment in the monolayer. Our results are consistent with first-principles calculations for the magnetic configurations with the lowest energy, i.e., antiferromagnetic V, Cr, and Mn, and ferromagnetic Fe and Co monolayers on Ag(100).