  We investigate the electronic structure of a complex conventional
superconductor, ZrB12 employing high resolution photoemission spectroscopy and
ab initio band structure calculations. The experimental valence band spectra
could be described reasonably well within the local density approximation.
Energy bands close to the Fermi level possess t_(2g) symmetry and the Fermi
level is found to be in the proximity of quantum fluctuation regime. The
spectral lineshape in the high resolution spectra is complex exhibiting
signature of a deviation from Fermi liquid behavior. A dip at the Fermi level
emerges above the superconducting transition temperature that gradually grows
with the decrease in temperature. The spectral simulation of the dip and
spectral lineshape based on a phenomenological self energy suggests a finite
electron pair lifetime and a pseudogap above the superconducting transition
temperature.
