  We have performed an angle-resolved photoemission study of the hole-overdoped
iron pnictide superconductor KFe2As2, which shows a low Tc of ~4 K. Most of the
observed Fermi surfaces show nearly two-dimensional shapes, while a band near
the Fermi level shows a strong dispersion along the kz direction and forms a
small three-dimensional hole pocket centered at the Z point, as predicted by
band-structure calculation. However, hole Fermi surfaces of yz and zx orbital
character centered at the \Gamma point of the two-dimensional Brillouin zone
are smaller than those predicted by the calculation while the other hole Fermi
surfaces of xy orbital character is much larger. Clover-shaped hole Fermi
surfaces around the corner of the 2D BZ are also larger than those predicted by
the calculation. These observations are consistent with the de Haas-van Alphen
measurement and indicate orbital-dependent electron correlation effects. The
effective masses of the energy bands show moderate to strong enhancement,
partly due to electron correlation and partly due to energy shifts from the
calculated band structure.
