Energy- and k -resolved mapping of the magnetic circular dichroism in threshold photoemission from Co films on Pt(111)

The magnetic circular dichroism in threshold photoemission (TPMCD) for perpendicularly magnetized fcc Co films on Pt(111) has been revisited. A complete mapping of the spectral function $I({E}_{B},{k}_{x},{k}_{y})$ (binding energy ${E}_{B}$, momentum parallel to surface ${k}_{x}$, ${k}_{y}$) and the corresponding TPMCD asymmetry distribution ${A}_{\mathrm{MCD}}({E}_{B},{k}_{x},{k}_{y})$ has been performed for one-photon and two-photon photoemission using time-of-flight momentum microscopy. The experimental results allow distinguishing direct from indirect transitions. The measurements reveal clear band features of direct transitions from bulk bands that show a nontrivial asymmetry pattern. …