Fe on Au(100): Quantum-well states down to a monolayer.

Abstract

Quantum-well states are observed for Fe films embedded in Au(100) using inverse photoemission. They can be analyzed with a simple interferometer model, using bulk states from the ${\mathrm{\ensuremath{\Gamma}}}_{12}$${\mathrm{\ensuremath{\Delta}}}_{1}$${\mathit{H}}_{15}$ band that are modulated by an envelope function with wavelengths in the order of 7--10 atomic layers (10--14 \AA{}). These states can be followed down to a monolayer, where two states are seen at 0.6 and 1.9 eV. They are tentatively assigned to the ${\mathrm{\ensuremath{\Delta}}}_{5}$\ensuremath{\downarrow} monolayer state and a ${\mathrm{\ensuremath{\Delta}}}_{1}$ quantum-well state. The resulting ferromagnetic exchange splitting of the ${\mathrm{\ensuremath{\Delta}}}_{5}$ is 2.7 eV, exceeding the splitting of 1.8--2.1 eV for the analogous bulk band.