  We present a study of the tetragonal to collapsed-tetragonal transition of
CaFe2As2 using angle-resolved photoemission experiments and dynamical mean
field theory-based electronic structure calculations. We observe that the
collapsed-tetragonal phase exhibits reduced correlations and a higher coherence
temperature due to the stronger Fe-As hybridization. Furthermore, a comparison
of measured photoemission spectra and theoretical spectral functions shows that
momentum-dependent corrections to the density functional band structure are
essential for the description of low-energy quasiparticle dispersions. We
introduce those using the recently proposed combined "Screened Exchange +
Dynamical Mean Field Theory" scheme.
