Critical test of CdTe(100) angle-resolved photoemission spectra with band-structure calculations

Angle-resolved synchrotron-radiation photoemission spectroscopy was used to determine the spin-orbit splitting between the Γ₈ and Γ₇ valence bands and to map the dispersion E(k) of the light- and heavy-hole bands as well as the split-off valence band along the [100] direction in CdTe. At a photon energy of h{ν}=10 eV, we find that a direct transition from the Brillouin-zone center is possible only from the highest occupied Γ₈ valence band, while for h{ν}=11 eV, the split-off Γ₇ band has comparable transition probability and also contributes to the normal-emission spectrum. The measured spin-orbit splitting {Δ}εs.o.=0.95 eV is in agreement with values reported from optical measurements. The experimentally determined valence-band critical-point energies are X₇{≤}-1.4 eV, X₆=-2.2 eV, and X₇=-4.4 eV. A comparison of these data points as well as the dispersion behavior of the top three valence bands is made with results based upon nonlocal pseudopotential, tight-binding, and self-consistent local-density approximations.